The influence of surgical exposure and orthodontic ...

FACULTEIT GENEESKUNDE EN

GEZONDHEIDSWETENSCHAPPEN

Academiejaar 2012 - 2013

The influence of surgical exposure and orthodontic

alignment of palatally impacted maxillary canines

on aesthetics and periodontics

Stéphanie EECKHOUT

Promotor: Prof. dr. Guy De Pauw

Copromotor: dr. Filiep Raes

Masterproef voorgedragen in de Master na Master Opleiding Orthodontie

De auteur(s) en de promotor geven de toelating deze Masterproef voor consultatie

beschikbaar te stellen en delen ervan te kopiëren voor persoonlijk gebruik. Elk ander gebruik

valt onder de beperkingen van het auteursrecht, in het bijzonder met betrekking tot de

verplichting uitdrukkelijk de bron te vermelden bij het aanhalen van resultaten uit deze

Masterproef.

30 april 2013

Stéphanie Eeckhout Prof. dr. Guy De Pauw

Voorwoord

De afgelopen drie jaar heb ik mijn theoretische kennis in de praktijk toegepast en voor het

eerst zelf een wetenschappelijk onderzoek uitgevoerd. Dat dit niet altijd zonder slag of stoot is

gegaan moge duidelijk zijn. Maar het is alle moeite zeker waard gebleken en ik blik dan ook

met trots terug op een succesvolle afronding van mijn onderzoek.

Graag had ik van de gelegenheid gebruik gemaakt om enkele mensen te bedanken. Allereerst

wil ik mijn dank betuigen aan mijn promotor Prof. dr. Guy De Pauw. Enerzijds om mij te

begeleiden bij deze thesis en mijn vele vragen op te lossen tijdens de onderzoeks- en in het

specifiek statistiekbesprekingen. Anderzijds om mij de kans te hebben gegeven om een

opleiding als specialist in de Orthodontie te kunnen starten. Het is een droom van mij die

werkelijkheid is geworden en hiervoor kan ik hem niet genoeg bedanken!

Ook mijn copromotor Dr. Filiep Raes wil ik graag bedanken voor de waardevolle tips en

feedback en om zijn kennis in de parodontologie ter beschikking te stellen van dit onderzoek.

Voor de begeleiding bij het verwerken van de gegevens heb ik beroep kunnen doen op

Mevrouw Roos Colman die steeds met zeer veel geduld al mijn vragen heeft beantwoord.

Een speciaal woord van dank gaat uit naar mijn ouders. Ik ben hen dankbaar dat ze mij de

kans hebben gegevens om deze studies aan te vatten en dat ze mij hierin steeds hebben

aangemoedigd. Ze hebben mij bewust gemaakt van mijn capaciteiten en het is dankzij hen dat

ik vandaag sta waar ik wil staan.

Ook mijn 3 “musketier” vriendinnetjes Eline, Elisabeth en Sophie en mijn lieftallige “ortho”

collega’tjes wil ik graag bedanken voor alle leuke momenten samen, maar ook voor de steun

tijdens de “pieker”momentjes. Dankzij jullie zal ik voor altijd een prachtige souvenir hebben

aan mijn opleiding in de p8.

Als laatste wil ik graag mijn vriend Thomas bedanken. Zijn positieve blik op alles en

onuitputtelijk enthousiasme werken aanstekelijk en gaven mij steeds dat extra beetje energie

om door te gaan als het even wat moeilijker ging. Mede door de liefde, onaflaatbare steun en

ontspannende momenten die jij mij hebt gegeven, werden deze drie afgelopen jaren een tijd

om nooit te vergeten.

1 Abstract ............................................................................................................................... 1

2 Introduction ......................................................................................................................... 3

2.1 Definition of impaction .............................................................................................. 3

2.2 Maxillary canine impaction ........................................................................................ 3

2.2.1 Prevalence ............................................................................................................ 3

2.2.2 Etiology and complications .................................................................................. 4

2.2.3 Diagnosis .............................................................................................................. 5

2.2.4 Treatment options ................................................................................................. 7

2.3 Periodontics .............................................................................................................. 11

2.3.1 Anatomy of the periodontium ............................................................................ 11

2.3.2 Assessment of inflammation .............................................................................. 12

2.3.3 Assessment of periodontal tissue support .......................................................... 13

2.3.4 Radiographic assessment of alveolar bone loss ................................................. 13

2.3.5 Impacted canines and periodontics .................................................................... 13

2.4 Aesthetics ................................................................................................................. 14

2.5 Radiographic assessment .......................................................................................... 15

2.6 Aim of the study ....................................................................................................... 15

3 Materials & methods ......................................................................................................... 16

3.1 Research of literature ............................................................................................... 16

3.2 Sample selection ....................................................................................................... 18

3.3 Data collection .......................................................................................................... 19

3.3.1 Degree of impaction ........................................................................................... 19

3.3.2 Biotype ............................................................................................................... 19

3.3.3 Plaque and Gingival Index ................................................................................. 20

3.3.4 Pocket depth ....................................................................................................... 20

3.3.5 Alveolar bone height .......................................................................................... 20

3.3.6 Colour ................................................................................................................. 21

3.3.7 Torque ................................................................................................................ 21

3.3.8 Midline deviation ............................................................................................... 21

3.3.9 Pink Esthetic Score and Canine Esthetic Score ................................................. 22

3.4 Statistical data analysis ............................................................................................. 25

3.4.1 Null hypothesis ................................................................................................... 25

3.4.2 Statistical tests .................................................................................................... 26

3.4.3 Error of method .................................................................................................. 26

4 Results ............................................................................................................................... 28

4.1 Biotype ..................................................................................................................... 28

4.2 Plaque Index ............................................................................................................. 29

4.3 Gingival Index .......................................................................................................... 31

4.4 Pocket depth ............................................................................................................. 32

4.5 Alveolar bone height ................................................................................................ 33

4.6 Colour ....................................................................................................................... 33

4.7 Torque ...................................................................................................................... 34

4.8 Midline deviation ..................................................................................................... 34

4.9 Pink Esthetic Score and Canine Esthetic Score ....................................................... 35

4.9.1 Overall score ...................................................................................................... 35

4.9.2 Periodontists ....................................................................................................... 35

4.9.3 Orthodontists ...................................................................................................... 36

4.9.4 General dentists .................................................................................................. 36

4.9.5 Comparison between the different dental groups ............................................... 36

4.9.6 Different parameters of the PES ......................................................................... 37

4.9.7 Different parameters of the CES ........................................................................ 39

5 Discussion ......................................................................................................................... 42

5.1 Surgical exposure ..................................................................................................... 42

5.2 Periodontics .............................................................................................................. 44

5.2.1 Plaque and Gingival Index ................................................................................. 44

5.2.2 Pocket depth ....................................................................................................... 45

5.2.3 Alveolar bone height .......................................................................................... 46

5.2.4 Biotype ............................................................................................................... 47

5.3 Aesthetics ................................................................................................................. 47

5.4 Radiographic assessment .......................................................................................... 48

5.5 PES and CES evaluation by different dental groups ................................................ 49

5.6 Critical evaluation .................................................................................................... 50

6 Conclusion ........................................................................................................................ 51

7 References ......................................................................................................................... 52

1

1 Abstract

DOEL: De invloed van het chirurgisch vrijleggen en orthodontisch aligneren van palataal

ingesloten bovenhoektanden op esthetiek en het parodontium te onderzoeken.

MATERIAAL EN METHODEN: Eénentwintig patiënten met unilateraal palataal

ingesloten bovenhoektanden werden onderzocht minstens één jaar na het beëindigen van de

orthodontische behandeling. Verschillende parameters (Gingivaal en Plaque Index, pocket

diepte, alveolaire bothoogte, torque, middenlijndeviatie en kleur) werden gemeten door één

onderzoeker. De contralaterale niet-geïmpacteerde hoektanden werden gebruikt als controle

groep. Een Periodontal Esthetic Score (PES) en Canine Esthetic Score (CES) werden

uitgevoerd door 10 orthodontisten, 10 parodontologen en 10 algemeen tandartsen.

Verschillende statistische testen werden uitgevoerd (p< 0.05).

RESULTATEN: Er waren geen significante verschillen voor de Gingivaal Index, Plaque

Index, torque en middenlijndeviatie. Significante verschillen werden gevonden voor de pocket

diepte mesiopalataal van de hoektand (p=0.046) en distopalataal van de laterale snijtand

(p=0.048) en voor de alveolaire bothoogte distaal van de laterale snijtand (p=0.003) en

mesiaal (p<0.001) en distaal van de hoektand (p=0.021). De totale gemiddelde score voor de

PES was 7.6 ter hoogte van de impactie kant en 8.4 ter hoogte van de non-impactie kant. De

totale gemiddelde score voor de CES was 5.9 ter hoogte van de impactie kant en 6.3 ter

hoogte van de non-impactie kant. De parodontologen hadden de neiging om de PES lager te

scoren ter hoogte van de impactie kant in vergelijking met de andere twee groepen. Voor de

CES werden geen significante verschillen gevonden tussen de drie groepen.

CONCLUSIE: Er werden geen significante verschillen gevonden tussen de geïmpacteerde en

niet-geïmpacteerde hoektanden voor de verschillende gemeten parameters, enkel voor de

alveolaire bothoogte. In de drie verschillende tandheelkundige groepen waren de gemiddelde

scores voor de PES en CES lager ter hoogte van de geïmpacteerde hoektanden.

Dit abstract werd aanvaard door de European Orthodontic Society en zal voorgesteld worden

in juni 2013 op het jaarlijks Europees congres in Reykjavik (IJsland) als een poster.

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AIM: To investigate the influence of surgical exposure and orthodontic alignment of palatally

impacted maxillary canines on different aesthetic and periodontal parameters.

MATERIALS AND METHODS: Twenty-one patients with unilateral palatally impacted

maxillary canines were examined at least one year after orthodontic treatment. Different

parameters (Gingival and Plaque Index, pocket depth, alveolar bone height, torque, midline

deviation and colour) were measured by one operator. The contralateral non-impacted canines

were used as a control group. A Periodontal Esthetic Score (PES) and Canine Esthetic Score

(CES) were performed by 10 orthodontists, 10 periodontists and 10 general dentists. Different

statistical tests were performed (p< 0.05).

RESULTS: There were no significant differences in the Gingival Index, Plaque Index, torque

and midline deviation. Significant differences were found for the pocket depth at the

mesiopalatal side of the canine (p=0.046) and the distopalatal side of the lateral incisor

(p=0.048) and for the alveolar bone height at the distal side of the lateral incisor (p=0.003)

and the mesial (p<0.001) and distal side of the canine (p=0.021). The overall score for the

PES was 7.6 at the impaction site and 8.4 at the non-impaction site. The overall score for the

CES was 5.9 at the impaction site and 6.3 at the non-impaction site. The periodontists had a

tendency to score lower for the PES at the impaction site compared to the other dental groups.

For the CES no significant differences were found between the 3 groups.

CONCLUSION: There were no significant differences in the different measured parameters

between the impacted and non-impacted canines, except for the alveolar bone height.

In the different dental groups the overall scores for the PES and CES were lower for the

impacted canines.

This abstract was accepted by the European Orthodontic Society and will be presented as a

poster in June 2013 at the annual European congress in Reykjavik (Iceland).

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2 Introduction

2.1 Definition of impaction

Impaction of a tooth is a condition in which an unerupted tooth is embedded in the bone such

that its eruption is prevented (1).

Under normal circumstances a tooth erupts with a developing root and with approximately

three-quarters of its final root length. We may therefore take this as a diagnostic baseline from

which to assess the eruption of teeth in general. Thus, should an erupted tooth have less root

development, it would be appropriate to label it as ‘prematurely erupted’. On the other hand,

if an unerupted tooth has a more completely developed root we can consider this tooth to be

‘impacted’ (2).

2.2 Maxillary canine impaction

The canine is situated in a strategic position between the anterior and posterior segment of the

dental arch and plays an important role in functional occlusion and aesthetics (3, 4).

Maxillary canines have the longest period of development, as well as the longest and most

tortuous course to travel from their point of formation until they reach their final destination

in full occlusion (5).

Palatally impacted maxillary canines are a dilemma for the patient, as well as for the

orthodontist. To expose them, the oral surgeon, orthodontist, and periodontist should choose a

safe procedure that results in a healthy periodontium. If not aligned, an impacted canine can

cause root resorption of adjacent teeth, a compromised occlusion and un unpleasant

appearance (6).

2.2.1 Prevalence

After the third molar, the maxillary canine is the most frequently impacted tooth (7).

According to several authors the prevalence of impacted maxillary canines is 0.9-2.2% and, in

most cases, the impacted canines are ectopically positioned (8).

Eighty-five per cent of impacted maxillary permanent canines are palatal impactions, and 15%

are labial impactions (9-11). Inadequate arch space and a vertical developmental position are

often associated with buccal canine impactions. If buccally impacted canines erupt they do so

vertically, buccally and higher in the alveolus (10). Due to denser palatal bone and thicker

palatal mucosa, as well as a more horizontal position, palatally displaced canines rarely erupt

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without requiring complex orthodontic treatment

(12). Palatally erupting or impacted

maxillary canines occur twice as often in females than males, have a high family association

and are 5 times more common in Caucasians than Asians (12, 13). It is not unusual for

maxillary canine impaction to occur bilaterally, although unilateral ectopic eruptions are more

frequent (7).

2.2.2 Etiology and complications

In general, the causes for retarded eruption of teeth may be either generalized or localized (14,

15). Generalized causes include endocrine deficiencies, febrile diseases and irradiation,

among others. The most common causes for canine impactions are usually localized and are

the result of any one or a combination of the following factors:

tooth size-arch length discrepancies,

prolonged retention or early loss of the deciduous canine,

abnormal position of the tooth bud,

the presence of an alveolar cleft,

ankylosis,

cystic or neoplastic formation,

dilacerations of the root,

iatrogenic,

trauma,

idiopathic condition with no apparent cause (12).

More recently, the absence of the maxillary lateral incisor, variation in its root size and

variation in the timing of its root formation have been implicated as important causative

factors associated with canine impaction (16-18). It seems that the presence of the lateral

incisor root with the right length, formed at the right time, are important variables needed to

guide the mesially erupting canine in a more favourable distal and incisal direction. This is

called ‘the guidance theory’ by Miller (1963) and Bass (1967) (11, 17). They concluded that

in the absence of the guiding influence of the lateral incisor, the canine continues its eruption

in its initial mesial and palatal path. The tooth then becomes impacted in the palatal area,

posterior to the central incisors and fails to erupt in its due time, or even at all.

This multi-factorial cause may explain why canine impactions occur when both the rest of the

dentition and other dental relationships are apparently normal, with sufficient space available

for the eruption of the impacted tooth, whereas in other cases it is associated with other

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genetic anomalies present in adjacent or distant teeth. As a result, canine impaction can be

described as either an isolated localized phenomenon or of polygenic multi-factorial

inheritance (19).

Shafer et al.(20) suggested that the following complications might be associated with canine

impaction:

labial or lingual malpositioning of the impacted tooth,

migration of the neighbouring teeth and resultant loss of arch length,

internal resorption,

dentigerous cyst formation,

external root resorption of the impacted as well as the neighbouring teeth,

infections particularly associated with partial eruption,

referred pain,

various combinations of these complications.

These potential complications point to the need for closely observing the development and

eruption of these teeth during the "routine" periodic dental examination of the growing child

(20).

2.2.3 Diagnosis

Patients do not go to their dentist complaining of an impacted tooth. They are frequently

unaware that this abnormality exists, since there is no pain, discomfort or swelling. Neither is

it obvious to the patient that there is a missing tooth, since the deciduous predecessor is

usually retained. The vast majority of impacted teeth come to light by chance in routine dental

examination and are not the result of a patient’s direct complaint. As a general rule, it is the

paediatric dentist or general dental practitioner who, during a routine dental examination,

discovers and records the existence of a retained deciduous tooth (21).

2.2.3.1 Clinical inspection

It has been suggested that the following clinical signs might be indicative of canine impaction:

delayed eruption of the permanent canine or prolonged retention of the deciduous

canine beyond 14 to 15 years of age,

6

absence of a normal labial canine bulge; in other words, either inability to locate

canine position through intraoral palpation of the alveolar process or the presence of

an asymmetry in the canine bulge noted during alveolar palpation,

presence of a palatal bulge,

delayed eruption, distal tipping, or migration of the lateral incisor (3).

For an accurate diagnosis, the clinical examination should be supplemented with a

radiographic evaluation.

2.2.3.2 Radiographic evaluation

To obtain a proper pre-treatment assessment and treatment plan, it is essential to know the

exact position of both the crown and the root apex of the unerupted canine.

Periapical radiographs:

A single periapical film provides the clinician with a two-dimensional representation of the

dentition. It relates the canine to the neighbouring teeth both mesiodistally and

superoinferiorly. But to evaluate precisely the location of the canine buccolingually, a second

periapical film should be taken (3) applying the buccal object rule, or the rule of “same

lingual opposite buccal” introduced by Clark (22). This method involves 2 radiographs using

the same vertical angulations but taken at different horizontal angles. Owing to parallax, the

more distant object will appear to travel in the same direction as the tube shift, and the object

closer to the tube will appear to move in the opposite direction (22).

Occlusal radiographs:

Occlusal radiographs also help determine the buccolingual position of the impacted canine in

conjunction with the periapical films, on condition that the image of the impacted canine is

not superimposed on the other teeth (3).

Extraoral films:

Frontal and lateral cephalograms can sometimes be of aid in determining the position of the

impacted canine, particularly its relationship to other facial structures, such as the maxillary

sinus and the floor of the nose (3).

The lateral cephalogram reveals the anterior-posterior position, inclination and vertical

location of the canine (23).

A panoramic radiograph, in its central portion, shows the incisor region in the posterior-

anterior view, and will indicate a palatal displacement as an overlap of the impacted canine

with the roots of the incisors.

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CT-scan:

The fourth option is to use a computed tomography (CT) scan, which can help to localize the

tooth, as well as give additional information regarding any bony pathologic features

associated with the impacted tooth (24).

The proper localization of the impacted tooth plays a crucial role in determining:

the feasibility as well as the proper access for the surgical approach,

the proper direction for the application of orthodontic forces,

the extent of the root resorption and damage to the adjacent teeth (3).

2.2.4 Treatment options

2.2.4.1 Prevention

If the clinician detects early signs of ectopic eruption of the canines, an attempt should be

made to prevent their impaction and its potential sequalae. Selective extraction of the

deciduous canines as early as 8 or 9 years of age has been suggested as an interceptive

approach to canine impaction in Class I uncrowded cases (25). Ericson and Kurol suggested

that the removal of the deciduous canine before 11 years of age will normalize the position of

the ectopically erupting permanent canines in 91% of the cases, if the canine crown is distal to

the midline of the lateral incisor. Conversely, the success rate is only 64% if the canine crown

is mesial to the midline of the lateral incisor (26).

2.2.4.2 No treatment

If the patient does not desire treatment, the clinician should periodically evaluate the impacted

tooth for any pathological changes. The long-term prognosis for retaining the deciduous

canine is poor, regardless of its root length and how aesthetically acceptable its crown is. This

is because, in most cases, the root will eventually resorb and the deciduous canine will have to

be extracted (12).

2.2.4.3 Autotransplantation

Autotransplantation involves atraumatic surgical removal of a tooth from its impacted or

ectopic site, the creation of a socket at the donor site, and then reimplantation of the tooth into

the correct position within the alveolus. The success of autotransplantation is thought to be

determined by a number of factors, which include patient age, developmental stage of the

8

transplanted tooth, type of tooth transplanted, surgical technique employed, and extra-alveolar

time span before the tooth is transplanted (27-29).

A number of factors may lead a clinician to consider autotransplantation for an impacted

maxillary canine, e.g. teeth that are markedly displaced and a reluctance of the patient to wear

orthodontic appliances or undergo prolonged treatment to accommodate the canine with

orthodontic traction. Other factors include the presence of adequate space for transplantation

within the arch, poor prognosis associated with the primary canine, good prognosis for the

transplanted tooth (no evidence of ankylosis), and the potential for atraumatic removal

maintaining the viability of the periodontal ligament (27, 30, 31).

Orthodontic relocation of impacted teeth might necessitate an extended period of treatment.

Additionally, the impacted tooth might ankylose; its pulp might become nonvital; its roots or

those of adjacent teeth might resorb; and the local periodontium might be damaged (32).

2.2.4.4 Extraction

2.2.4.4.1 Canines

Although extraction of the impacted canine might provide the most immediate solution,

restoration of occlusal function and aesthetics will be compromised. Establishing canine

guidance restoratively is not recommended; restorative alternatives for replacing the removed

canines are limited, and facial aesthetics will be compromised because of inadequate space

(33).

The extraction of the canine, although seldom considered, might be a viable option in the

following situations:

if it is ankylosed and cannot be transplanted,

if it is undergoing external or internal root resorption,

if its root is severely dilacerated,

if the impaction is severe, for example, if the canine is lodged between the roots of the

central and lateral incisors, and orthodontic movement will jeopardize these teeth,

if the occlusion is acceptable, with the first premolar in the position of the canine and

with an otherwise functional occlusion with well-aligned teeth,

if there are pathological changes, such as cystic formation, infection, etc., and the

patient does not desire orthodontic treatment (12).

9

2.2.4.4.2 Lateral incisors

Impacted canines are sometimes associated with anomalous lateral incisors. At the end of the

treatment procedure, it is often necessary to alter the shape of these teeth by prosthetic

crowning, laminates or composite build-ups, in order to make them aesthetically acceptable,

particularly those that are peg-shaped. Palatal canine cases generally have spaced dentitions,

comprising small teeth, so that crowding and the need for extractions in the overall treatment

is unusual. Nevertheless, if extraction has to be made to treat the overall malocclusion in these

cases, consideration should be given to the extraction of these malformed lateral incisors, as

an alternative to the conventional but healthy and anatomically perfect first premolars.

Extraction of the lateral incisor is not a suitable procedure in most cases, but in those patients

where it is indicated, treatment time may often be very short. However, a normally sized

canine adjacent to a central incisor may create an unsatisfactory appearance, particularly if the

central incisor has a poor profile. Furthermore, by lining up the canine and the first premolar

in place of the lateral incisor and canine, a discrepancy between upper and lower tooth sizes

may compromise the occlusion (21).

2.2.4.4.3 First premolars

Within the minority group of patients with impacted canines who are considered to be

extraction cases, a Class II relation or bimaxillary protrusion, the choice of teeth for extraction

usually devolves upon the first or second premolars. Extraction of the first premolars offer

much potential benefit to the displaced canine because the proximity of these teeth facilitates

the immediate provision of space close to the canine. It also affords considerable opportunity

for a spontaneous improvement in the canine position, during the early leveling and aligning

stages of the mechanotherapy (21).

2.2.4.5 Surgical exposure

Ectopic labially positioned canines may erupt on their own without surgical exposure or

orthodontic treatment, frequently high in the sulcus or alveolar ridge. Conversely, palatally

impacted canines seldom erupt without intervention. It is believed that this obstructed

eruption is caused by the thickness of the palatal cortical bone as well as the dense, thick, and

resistant palatal mucosa. Palatally impacted canines are more often inclined in a

horizontal/oblique direction, whereas labial impactions usually offer a more favorable vertical

10

angulation. Yet the latter are still considered difficult because of the needed delicacy in

managing the associated hard and soft tissues (12).

2.2.4.5.1 Open approach

Either an open or a closed surgical approach can be used to uncover the crown of an impacted

tooth and to place an orthodontic attachment. The position of the impacted tooth within the

alveolus generally determines which approach is used.

In the open approach (OA), a gingival flap is reflected or soft tissue is excised, and bone over

the crown is removed, creating a window to expose the crown of the tooth. A periodontal

pack is placed to prevent the window from closing (33).

The advantages of the OA include the orthodontist’s ability to observe the impacted tooth as

it is moved (34, 35) and faster eruption (34). In addition, bonding can be undertaken later

under more ideal conditions. The main problems associated with this method are difficulty in

cleaning the area, discomfort associated with the wound and multiple periodontal concerns,

including gingival recession (34, 36, 37), bone loss, decreased width of keratinized gingiva

(37, 38), delayed periodontal healing and gingival inflammation (33).

Even when a decision has been made to undertake an open approach, there are two further

options to be considered. The first of these is to permit natural eruption of the canine and the

second is to place an attachment on the tooth at or very soon after surgery to facilitate

orthodontically-induced eruption (39).

The spontaneous eruption is most useful when the canine has a correct axial inclination and

does not need to be uprighted during its eruption. The main disadvantages of this approach are

the spontaneous but slow canine eruption, the increased treatment time, and the inability to

influence the path of eruption of the impacted canine.

One of the important advantages of the placement of an attachment is that when the force is

applied to the impacted tooth, the clinician is able to visualize and better control the direction

of tooth movement. This avoids moving the impacted tooth into the roots of the neighbouring

teeth (12).

2.2.4.5.2 Closed approach

In the closed approach (CA), a gingival flap is reflected, exposing the crown of the impacted

tooth. The bone covering the crown is removed, and an orthodontic attachment is placed. The

flap is replaced with a chain or wire extending from the attachment into the oral cavity (33).

11

This procedure enables oral hygiene to be maintained more readily and reduces post-operative

discomfort. However, direct inspection of the tooth is not possible post-operatively and it may

be difficult to keep the tooth sufficiently dry during surgery to allow successful bonding (40).

2.3 Periodontics

2.3.1 Anatomy of the periodontium

The periodontium comprises the following tissues:

the gingiva

the periodontal ligament

the root cementum

the alveolar bone.

The gingiva is that part of the masticatory mucosa which covers the alveolar process and

surrounds the cervical portion of the teeth. It consist of an epithelial layer and an underlying

connective tissue layer called the ‘lamina propria’. The gingiva obtains its final shape and

texture in conjunction with eruption of the teeth.

In the coronal direction the coral pink gingiva terminates in the ‘free gingival margin’. In the

apical direction the gingiva is continuous with the loose, darker red ‘alveolar mucosa’ from

which the gingiva is separated by a, usually, easily recognizable borderline called the

‘mucogingival junction/line’.

Two parts of the gingiva can be differentiated: the free gingiva and the attached gingiva.

The free gingiva is coral pink, has a dull surface and firm consistency. It comprises the

gingival tissue at the vestibular and lingual/palatal aspects of the teeth, and the interdental

papillae. On the vestibular and lingual side of the teeth, the free gingiva extends from the

gingival margin in apical direction to the ‘free gingival groove’ which is positioned at a level

corresponding to the level of the ‘cemento-enamel junction’ (CEJ). The attached gingiva

extends in apical direction to the mucogingival junction where it becomes continuous with the

alveolar mucosa. It is firmly attached to the underlying alveolar bone and cementum by

connective tissue fibers and is therefore immobile in relation to the underlying tissue. The

alveolar mucosa, on the other hand, is mobile in relation to the underlying tissue.

The free gingival margin is often rounded in such a way that a small invagination or ‘sulcus’

is formed between the tooth and the gingiva. When a periodontal probe (= a long, thin,

12

blunted instrument that has markings inscribed on the head of the instrument for accurate

measuring of the pocket depth around a tooth in order to establish the state of the health of the

periodontium) is inserted into this invagination and, further apically, towards the cemento-

enamel junction, the gingival tissue is separated from the tooth, and a ‘gingival pocket’ is

artificially opened. Thus, in normal or clinically healthy gingiva there is in fact no ‘gingival

pocket’ present but the gingiva is in close contact with the enamel surface. After completed

tooth eruption, the free gingival margin is located on the enamel surface approximately 1.5 to

2mm coronal to the cemento-enamel junction.

The periodontal ligament is the soft, richly vascular and cellular connective tissue which

surrounds the roots of the teeth and joins the root cementum with the socket wall. In the

coronal direction, the periodontal ligament is continuous with the lamina propria of the

gingiva and is demarcated from the gingiva by the collagen fiber bundles which connect the

alveolar bone crest with the root.

The part of the alveolar bone which covers the alveolus is called the ‘lamina dura’. The

portion of the alveolar process which in the radiograph has the appearance of a meshwork is

called the ‘spongy bone’.

The periodontal ligament is situated in the space between the roots of the teeth and the lamina

dura and permits forces to be distributed to and resorbed by the alveolar process via the

lamina dura. The periodontal ligament is also essential for mobility of the teeth.

The root cementum is a specialized mineralized tissue covering the root surfaces.

The alveolar process is defined as the parts of the maxilla and the mandible that form and

support the sockets of the teeth. (41)

2.3.2 Assessment of inflammation

Presence of inflammation in the marginal portion of the gingiva is usually recorded by means

of probing assessments, according to the principles of the Gingival Index by Loë (42). A

parallel index for scoring plaque deposits (Plaque Index) was introduced by Silness & Loë

(43). Simplified variants of both the Gingival and the Plaque Index (44) have been extensively

used, assessing presence/absence of inflammation or plaque respectively in a binomial fashion

(dichotomous scoring). In such systems, bleeding from the gingival margin and visible plaque

score “1”, while absence of bleeding and no visible plaque score “0”. Bleeding after probing

to the base of the probable pocket (Gingival Sulcus Bleeding Index) has been a common way

of assessing presence of subgingival inflammation (45). In this dichotomous registration, “1”

13

is scored in case bleeding emerges within 15 seconds after probing. Presence/absence of

bleeding on probing to the base of the pocket tends to increasingly substitute the use of the

Gingival Index in epidemiological studies. (41)

2.3.3 Assessment of periodontal tissue support

In contemporary epidemiological studies, loss of periodontal tissue support is assessed by

measurements of pocket depth and attachment level. Probing pocket depth (PPD) is defined as

the distance from the gingival margin to the location of the tip of a periodontal probe inserted

in the pocket with moderate probing force. Likewise, probing attachment level (PAL) or

clinical attachment level (CAL) is defined as the distance from the cemento-enamel junction

(CEJ) to the location of the inserted probe tip. Probing assessments may be carried out at

different locations of the tooth circumference (buccal, lingual, mesial or distal sites). The

number of probing assessments per tooth has varied in epidemiological studies from two to

six, while the examination may either include all present teeth (full-mouth) or a subset of

index teeth (partial-mouth examination). (41)

2.3.4 Radiographic assessment of alveolar bone loss

Radiographs have been commonly used in cross-sectional epidemiological studies to evaluate

the result of periodontal disease on the supporting tissues rather than the presence of the

disease itself. Assessments of bone loss in intraoral radiographs are usually performed by

evaluating a multitude of qualitative and quantitative features of the visualized interproximal

bone, e.g. :

the presence of an intact lamina dura,

the width of the periodontal ligament space,

the morphology of the bone crest (“even” or “angular” appearance),

the distance between the CEJ and the most coronal level at which the periodontal

ligament space is considered to retain a normal width.

The threshold for bone loss (= the CEJ-bone crest distance) considered to indicate that bone

loss has occurred, varies between 1 and 3mm in different studies. (41)

2.3.5 Impacted canines and periodontics

Subgingival plaque is a major etiological factor in the beginning progression and recurrence

of periodontal disease (46-49). Periodontal complications associated with orthodontic

eruption of impacted teeth arise from inadequate oral hygiene.

14

Surgically uncovering impacted teeth exposes deeper areas of the periodontium to the

destructive effects of poor plaque control.

When a ‘closed approach’ surgery is used, the amount of plaque in the pericoronal area of an

impacted tooth might be reduced, but plaque removal becomes impossible.

The ‘open approach’ surgery creates an atypical soft tissue architecture that enhances plaque

accumulation while challenging plaque control measures. Routine plaque control measures

must be adapted to address the exposed tooth’s atypical position in the alveolar process and to

the crater-like soft tissue defect created by an open approach (33). This method is also

associated with multiple other periodontal concerns, including gingival recession, bone loss

(34), decreased width of keratinized gingiva (37, 50), delayed periodontal healing and

gingival inflammation (37).

2.4 Aesthetics

Regarding aesthetics of post-treatment impacted canines, there are several aspects where

attention should be brought upon:

canine position,

colour,

dental midline deviation,

gingival height.

Canine position in the dental arch includes different aspects: crown tip level relative to the

adjacent teeth (i.e. intrusion/extrusion; this can only be measured if the canine crown height is

the same as the contralateral canine, otherwise it means that there are signs of tooth wear or

abrasion (8)) and torque difference compared to the contralateral canine. Torque can be

measured as the angle between the tangent of the canine and the frontal occlusal plane.

Tooth colour can be assessed by using a commercial shade guide (Vita porcelain shade guide,

Vita Zahnfabrik) (51).

Dental midline deviation is the difference in millimeters between the facial midline and the

dental midline.

Gingival height of the canines should be at the same level as the central incisors in frontal

sight.

15

2.5 Radiographic assessment

Ericson and Kurol proposed 3 criteria to investigate the prognosis for impacted canines on

panoramic X-rays (Fig. 1):

α-angle: the angle measured between the long axis of the impacted canine and the

midline,

d-distance: the distance between the canine cusp tip and the occlusal plane (from the

first molar to the incisal edge of the central incisor),

s-sector: the sector where the cusp of the impacted canine is located:

sector 1: between the midline and the axis of the central incisor,

sector 2: between the axis of the central incisor and the axis of the lateral

incisor,

sector 3: between the axis of the lateral incisor and the axis of the first

premolar (26).

These measurements are able to describe features of canine displacement in the bony

structures during mixed dentition, and they characterize the severity of subsequent impaction

of the canine in permanent dentition (52).

Figure 1. Panoramic radiographic features showing displacement of the upper left canine: α-angle, d-

distance, and s-sector (derived from (53)).

2.6 Aim of the study

The aim of this study is to investigate whether an open surgical exposure and orthodontic

alignment of palatally impacted maxillary canines has an influence on the aesthetic and

periodontal outcome when compared to the contralateral canines that erupted spontaneously.

16

3 Materials & methods

3.1 Research of literature

A search strategy was set up to identify the articles concerning the influence of surgical

exposure and orthodontic alignment of palatally impacted maxillary canines on aesthetics and

periodontics. The following search terms were used:

Impacted => “Tooh, impacted” [MeSH], “impaction”

Canine => “Cuspid” [MeSH], “canine”

Maxillary => “maxil*”

Palatally => “palatal*”

Surgical => “Surgery, Oral” [MeSH], “Tooth, Impacted/surgery” [MeSH], “Tooth,

Impacted/therapy” [MeSH], “surg*”

Exposure => “expos*”

Orthodontics => “Orthodontics” [MeSH], “orthodon*”

Aesthetics => “Esthetics, Dental” [MeSH], “aesthet*”, “esthet*”

Periodontics => “Periodontics” [MeSH], “period*”

Pink Esthetic Score (PES) => “Pink esthetic socre”, “Pink aesthetic score”

White Esthetic Score (WES) => “White esthetic score”, “White aesthetic score”

Radiograph => “Radiography, Dental” [MeSH], “Radiography, Panoramic” [MeSH],

“orthopantomogr*”, “radiogra*”, “X-ray Film” [MeSH], “X-ray*”.

The cursive words stand for the combination of the different search terms per term. Different

electronic databases (Medline, Web of Science, Cochrane) were used. The search was

restricted to English and Dutch literature only, case reports were excluded and after reading

the abstracts only the relevant articles that related to impacted canines were selected. After

discarding duplicates a final sample of 82 articles was selected (Table 1).

Database Search terms Results Selected

Medline

Impacted AND canine 1254 /

Impacted AND canine AND periodontics 166 36

Impacted AND canine AND aesthetics 50 5

Impacted AND canine AND orthodontics 620 /

Impacted AND canine AND surgical 819 /

17

Impacted AND canine AND exposure 146 /

Impacted AND canine AND exposure AND periodontics 63 23

Impacted AND canine AND exposure AND aesthetics 10 5

Impacted AND canine AND exposure AND orthodontics 118 /

Impacted AND canine AND exposure AND surgical 127 /

Impacted AND canine AND palatal 216 /

Impacted AND canine AND palatal AND periodontics 48 22

Impacted AND canine AND palatal AND aesthetics 16 4

Impacted AND canine AND palatal AND orthodontics 159 /

Impacted AND canine AND palatal AND surgical 149 /

Impacted AND canine AND palatal AND exposure 51 23

Impacted AND canine AND palatal AND exposure AND

periodontics

22 13


aesthetics

4 /


orthodontics

45 24


surgical

48 23

Impacted AND canine AND radiograph 454 /

Impacted AND canine AND radiograph AND palatal 90 22

Pink esthetic score 39 5

White esthetic score 30 2

Web of

Science

Impacted AND canine AND periodontics 236 /

Impacted AND canine AND aesthetics 38 5

Impacted AND canine AND exposure AND periodontics 59 12

Impacted AND canine AND palatal AND exposure 29 16

Impacted AND canine AND radiograph AND palatal 50 11

Pink esthetic score 30 4

Cochrane Impaction 7 1

Final selection 82

Table 1. Research of literature.

18

3.2 Sample selection

This study has been approved by the Ethical Committee of Ghent (2011/506).

The database and all the plaster casts of all the patients ever treated at the University Hospital

of Ghent were searched for unilateral palatally impacted maxillary canines.

Inclusion criteria:

- the patients all had a panoramic X-ray from the start of treatment on which the severity of

the impaction was measured according to Ericson and Kurol (26),

- the patients had no medical history,

- the orthodontic treatment was at least finished for 1 year.

Fourty five patients were taken into consideration from which 32 patients were contacted

successfully. From these 32 patients 26 patients agreed to participate, 3 disagreed and 3 are

still in orthodontic treatment. Five patients didn’t show up at their appointment.

The final sample contained 21 patients with unilateral palatally impacted maxillary canines.

All canines were surgically exposed with an open exposure at the department of Oral and

Maxillofacial Surgery at the University Hospital of Ghent. Afterwards all patients were

orthodontically treated at the department of Orthodontics at the University Hospital of Ghent.

The contralateral non-impacted canines were used as a control group.

All patients signed an informed consent (appendix 1&2) and agreed to make an appointment

to collect the following data:

- impressions of the upper and lower jaw,

- intra-oral pictures (frontal, upper, left and right side) and an extra-oral picture (frontal),

- pocket depth, Plaque- and Gingival Index of the upper canine and its two neighbouring

teeth,

- colour measurements of the maxillary canines (VITA Easyshade®),

- peri-apical radiographs of the maxillary canines and their two neighbouring teeth.

From these data measurements were made concerning periodontics (Plaque Index, Gingival

Index, pocket depth, alveolar bone height) and aesthetics (midline deviation, torque

difference, colour and gingival aesthetics).

19

3.3 Data collection

3.3.1 Degree of impaction

To investigate the severity of the impaction a modification of the criteria proposed by Ericson

and Kurol (26) as mentioned in “2.5 radiographic assessment” was used. The criteria for the

α-angle and s-sector remained the same, while the d-distance was modified by dividing it into

3 groups according to the location of the cusp tip in relationship to the root of the lateral

incisor:

d1: the cusp is located in the apical third of the root of the lateral incisor

d2: the cusp is located in the middle third of the root of the lateral incisor

d3: the cusp is located in the coronal third of the root of the lateral incisor

3.3.2 Biotype

The identification of the gingival biotype is important because differences in gingival and

osseous architecture have been shown to exhibit a significant impact on the outcome of

restorative therapy (54). More gingival recession was found following regenerative surgery in

patients with a thin gingiva (55, 56). Especially patients with a thin-scalloped biotype seem at

risk for aesthetic failure and therefore need to be accurately identified (57). Patients with a

thick gingiva have been shown to be relatively resistant to gingival recession following

surgical and/or restorative therapy (54-56).

The evaluation of the gingival thickness was based on the transparency of a periodontal probe

through the gingival margin while probing the sulcus at the midfacial aspect of the central

maxillary incisor (58) (Fig. 2). If the outline of the underlying periodontal probe could be seen

through the gingiva, it was categorized as thin (score: 0); if not, it was categorized as thick

(score: 1). This method for assessment of the gingival thickness is a simple and reproducible

method (59).

Figure 2. Intra-oral picture showing the evaluation of the gingival thickness based on the transparency of

a periodontal probe.

20

3.3.3 Plaque and Gingival Index

As mentioned above in “2.3.2 assessment of inflammation”, the presence of inflammation in

the marginal portion of the gingiva is usually recorded by means of probing assessments,

according to the principles of the Gingival Index by Loë (42). A parallel index for scoring

plaque deposits (Plaque Index) was introduced by Silness & Loë (43) .

In this study the simplified variants of the Gingival Sulcus Bleeding Index (45) and the Plaque

Index (44) were used. Bleeding from the gingival margin within 15 seconds after probing and

visible plaque scored “1”, while absence of bleeding and no visible plaque scored “0”. The

Plaque and Gingival Index were measured for the upper canines and their two neighbouring

teeth.

3.3.4 Pocket depth

Probing pocket depth (PPD) is defined as the distance from the gingival margin to the location

of the tip of a periodontal probe inserted in the pocket with moderate probing force.

In this study probing assessments were carried out at 6 different locations of the tooth

circumference (mesiobuccal, buccal, distobuccal, mesiolingual, lingual and distolingual) for

the upper canines and their two neighbouring teeth.

3.3.5 Alveolar bone height

Figure 3. Peri-apical radiograph showing the measurement of the alveolar bone height.

To measure the alveolar bone height (= the CEJ-bone crest distance) a peri-apical radiograph

of the maxillary canine and its two neighbouring teeth was taken at the impaction and non-

impaction side of the patient. A periodontal probe was placed on the canine while taking the

radiograph so the X-rays could be calibrated with ImageJ®. A line was drawn through the

21

mesial and distal aspect of the CEJ of the canine (Adobe Photoshop CS5.1®) and

perpendicular to this line the distance to the bone crest was measured with ImageJ®.

In this study the alveolar bone height was measured at 4 sites: the distal side of the lateral

incisor, the mesial and distal side of the canine and the mesial side of the first premolar (Fig.

3).

3.3.6 Colour

Tooth colour was assessed in the patient’s mouth by using the VITA Classical shade guide®.

This device enables objective determination of the tooth colour. In this study the colour of

both the impacted and non-impacted canine was measured.

3.3.7 Torque

Torque of the canines can be measured on dental casts and intra-oral radiographs as the angle

between the tangent of the labial surface of the canine and the frontal occlusal plane (Fig. 4).

In this study the torque of both the impacted and non-impacted canine was measured by using

ImageJ® and Adobe Photoshop CS5.1®.

Figure 4. Intra-oral picture showing the measurement of torque of the canines.

3.3.8 Midline deviation

Dental midline deviation is the difference in millimeters between the facial midline and the

dental midline. This can be measured on an extra-oral photograph by drawing a line through

the two pupils of the patient and taking the perpendicular line through the middle of the two

canthi. The distance from this line to the dental midline shows the midline deviation in

22

millimeters. In this study the midline deviation was measured by using ImageJ® and Adobe

Photoshop CS5.1®.

The eight parameters mentioned above were measured and calculated by one operator.

3.3.9 Pink Esthetic Score and Canine Esthetic Score

For scoring the gingival aspects and aesthetics of the canines a modification of the Pink

Esthetic Score (PES) and White Esthetic score (WES) by Belser (60) was used.

3.3.9.1 Pink Esthetic Score

The Pink Esthetic Score (Fig. 5) comprises the following 5 parameters:

score 0 score 1 score 2

1 mesial papilla absent incomplete complete

2 distal papilla absent incomplete complete

3 curvature of the soft tissue

margin

unnatural fairly natural natural

4 level of the soft tissue margin major

discrepancy

>2mm

minor

discrepancy

1-2 mm

no discrepancy

<1mm

5 root convexity/ soft tissue

colour and texture

major

discrepancy

minor

discrepancy

no discrepancy

Figure 5. The 5 variables of the Pink Esthetic Score according to Belser (60).

For parameters 4 en 5 a comparison must be made with the upper left central incisor from

which we know that the level, colour and texture of the soft tissue should be the same as that

of the canine under ideal circumstances. The root convexity of the canine should be somewhat

more pronounced for the canine in comparison to the central incisor. Parameter 5 consists of 3

23

different variables. If these variables differ from one another than the variable with the lowest

score must be taken.

A score of 0, 1, or 2 is assigned to all five PES parameters for both canines. The five

described parameters (5x2) add up, under optimum conditions, to a score of 10, the threshold

for clinical acceptability is set at 6.

3.3.9.2 Canine Esthetic Score

A modification of the White Esthetic Score by Belser (60) was made especially for this study

and was given the name: the Canine Esthetic Score (CES).

The CES (Table 2) specifically focuses on the aesthetics of the canine crown and is based on

the 4 following parameters:

score 0 score 1 score 2

1 torque unacceptable clinically acceptable meets the criteria

2 uprighting over- or under

uprighted

clinically acceptable meets the criteria

3 colour bad average good

4 canine cusp major discrepancy

>2mm

minor discrepancy

1-2 mm

no discrepancy

<1mm Table 2. The 4 variables of the Canine Esthetic Score.

A score of 0, 1, or 2 is assigned to all four CES parameters for both canines.

Thus, in case of a perfectly aesthetic crown a total CES of 8 is reached.

3.3.9.2.1 Torque

Figure 6. Negative torque. Figure 7. Torque that meets the criteria.

24

To evaluate the torque or labiolingual crown inclination the ‘six keys to a normal occlusion’

by Andrews are used (61). The third key to a normal occlusion is crown inclination.

Crown inclination refers to the labiolingual or buccolingual inclination of the long axis of the

crown, not to the inclination of the long axis of the entire tooth.

Torque can be evaluated by drawing a tangent to the canine crown.

If the gingival portion of the tangent line (or of the crown) is lingual to the incisal portion,

than there is a positive torque. If the gingival portion of the tangent line (or of the crown) is

labial to the incisal portion, than there is a negative torque (Fig. 6). If the inclination of the

tangent line of the canine is slightly negative, than it meets up with the criteria (Fig. 7).

3.3.9.2.2 Uprighting

Figure 8. The second key to a normal occlusion: the crown angulation.

To evaluate the uprighting or the crown angulation of the canine, we make use of the second

key of Andrews. Crown angulation can be evaluated by drawing a line that passes along the

long axis of the crown through the most prominent part in the center of the labial or buccal

surface. This line is called the long axis of the clinical crown. If the gingival part of the long

axis of the canine crown is distal to the occlusal part of the line, it meets up with the criteria

(Fig. 8). (61)

3.3.9.2.3 Colour

To score the colour of the canine, the lower canine is used as a reference tooth.

25

3.3.9.2.4 Canine cusp

Figure 9. The canine cusp is situated on the same level as the incisal edges of the upper central incisors.

To evaluate the vertical position of the canine, a line is drawn through the incisal edges of the

upper central incisors. Under ideal circumstances, the tip of the canine cusp should be at the

same level of the incisal edges of the upper central incisors (Fig. 9).

3.3.9.3 Evaluation by different dental groups

To evaluate the gingival aspects and aesthetics of the canines 3 different dental groups, each

consisting of 10 persons, were asked to perform a PES and CES on all 21 patients. The

different dental groups were 10 periodontists, 10 orthodontists and 10 general dentists. After

explaining the scoring system of the PES and CES, a slideshow was played on a big screen

showing an overview of each patient’s intra oral pictures per slide. Without knowing which

canine was impacted at the start of treatment, they scored the upper left and right canine on

their gingival aspects and aesthetics.

This blind measurement will exclude the subjective influence of the investigator who knows

which canine was impacted initially.

The goal of this blind measurement is to examine if the different dental professionals can

point out the impacted canine and if there is a difference in scoring between the different

dental groups.

3.4 Statistical data analysis

All the data were exported to SPSS Statistics® (version 20) for statistical analysis.

3.4.1 Null hypothesis

The null hypothesis Ho = there is no statistically significant difference between the impacted

and non-impacted canine in regard to the periodontium and aesthetics after surgical exposure

and orthodontic alignment.

26

3.4.2 Statistical tests

To determine which statistical tests had to be performed, all parameters were put to a test of

normality: the Shapiro-Wilk test. If the parameters scored lower than 0.05, the null hypothesis

can be rejected and the values are not distributed according to the Gaussian ‘bell curve’. For

these parameters a non-parametric test should be used, that is the Wilcoxon matched-pairs

signed-ranks test. A paired test is used because the data are collected from the same patients.

If the parameters scored higher than 0.05, the null hypothesis is valid and the values are

distributed according to the Gaussian ‘bell curve’. For these parameters a parametric test

should be used, that is the Paired Student’s t-test.

To measure repeated observations of the same variable within one individual and under the

same experimental conditions a non parametric test for repeated measurements is used, that is

the Friedman test.

Dichotomous variables obtained by the same individuals in two different conditions can be

compared by using the McNemar test.

To evaluate the correlation between two variables the Spearman test is used.

3.4.3 Error of method

3.4.3.1 Intra-observer reliability

The intra-observer reliability of the clinician who performed all the measurements was

analysed. Therefore, one linear measurement (alveolar bone height), one angular

measurement (torque) and the midline deviation of 10 at randomly selected patients were re-

measured 4 weeks after the first recording by the same clinician. Dahlberg’s formula was used

to determine the random error (RE) of measurement. The Dahlberg formula is defined as:

√∑

‘d’ is the difference between the first and the second measure and ‘n’ is the sample size which

was re-measured.

The RE for the linear measurement = 0,03mm.

The RE for the angular measurement = 0,31°.

The RE for the midline deviation = 0,03mm.

27

3.4.3.2 Inter-observer reliability

The inter-observer reliability reflects the degree of agreement among raters. It gives a score of

how much homogeneity, or consensus, there is in the ratings given by different observers.

This can be determined by calculating the intraclass correlation coefficient (ICC). The ICC is

a value between ‘0’ and ‘1’. The closer the ICC approximates the ‘1’, the bigger the reliability.

There is no real consensus about which value the ICC has to reach to achieve a ‘good

reliability’. One of the possible classifications that can be used is that of Fleiss (62):

ICC > 0.75 ‘excellent’, ICC > 0.40 ‘average-good’, ICC < 0.40 ‘bad’.

In this investigation, the ICC was calculated for the PES and CES scored by the group of 10

orthodontists at two different time intervals:

The ICC for the PES at the first point of time was 0.74 (nearly excellent).

The ICC for the CES at the first point of time was 0.83 (excellent).

The ICC for the PES at the second point of time was 0.82 (excellent).

The ICC for the CES at the second point of time was 0.72 (nearly excellent).

From these findings we can conclude that both tests have a nearly excellent reliability.

//en.wiktionary.org/wiki/homogeneity

28

4 Results

4.1 Biotype

To evaluate the influence of the biotype on the PES at the impaction site, the PES was split up

into two groups: all the values beneath 7.5 and all the values above 7.5. Four patients had a

thin biotype and all four of them had a PES score above 7.5. Seventeen patients had a thick

biotype; nine of them had a PES score below 7.5 and eight had a PES score above 7.5 (Table

3). According to the Spearman test a negative correlation (-0.42) was found between the PES

and the biotype, however without any statistical significance.

biotype

thin thick total

PES_impaction

site

<7.5 0 9 9

>7.5 4 8 12

total 4 17 21

Table 3. Influence of the biotype on the PES at the impaction site.

To evaluate the influence of the biotype on the CES at the impaction site, the CES was split

up into two groups: all the values beneath 6 and all the values above 6. Four patients had a

thin biotype and all four of them had a CES score above 6. Seventeen patients had a thick

biotype; ten of them had a CES score below 6 and seven had a PES score above 6 (Table 4).

According to the Spearman test a statistically significant negative correlation (-0.46) was

found between the PES and the biotype (p=0.035). This correlation has no clinical

significance.

biotype

thin thick total

CES_impaction

site

<6 0 10 10

>6 4 7 11

total 4 17 21

Table 4. Influence of the biotype on the CES at the impaction site.

29

4.2 Plaque Index

The values for the Plaque Index (PI) at the impaction (I) site versus the non-impaction (NI)

site were compared using the McNemar test.

The Plaque Index for the lateral incisor:

PI-NI-lat inc

0 1 Total

PI-I-lat

inc

0 18 0 18

1 1 2 3

Total 19 2 21

Table 5. The Plaque Index for the lateral incisor.

At the impaction site “no plaque” (score “0”) was scored 18 times and “plaque” (score “1”)

was scored 3 times.

At the non-impaction site “no plaque” (score “0”) was scored 19 times and “plaque” (score

“1”) was scored 2 times.

No statistically significant differences were found (Table 5).

The Plaque Index for the canine:

PI-NI-canine

0 1 Total

PI-I-

canine

0 19 1 20

1 1 0 1

Total 20 1 21

Table 6. The Plaque Index for the canine.

30


was scored 1 time.


“1”) was scored 1 time.


The Plaque Index for the first premolar:

PI-NI-premolar

0 1 Total

PI-I-

premolar

0 19 0 19

1 1 1 2

Total 20 1 21

Table 7. The Plaque Index for the first premolar.


was scored 2 times.


“1”) was scored 1 time.


31

4.3 Gingival Index

The values for the gingival index (GI) at the impaction (I) site versus the non-impaction (NI)

site were compared using the McNemar test.

The Gingival Index for the lateral incisor:

GI-NI-lat inc

0 1 Total

GI-I-lat

inc

0 7 4 11

1 2 8 10

Total 9 12 21

Table 8. The Gingival Index for the lateral incisor.

At the impaction site “no bleeding” (score “0”) was scored 11 times and “bleeding” (score “1”)

was scored 10 times.

At the non-impaction site “no bleeding” (score “0”) was scored 9 times and “bleeding” (score



The Gingival Index for the canine:

GI-NI-canine

0 1 Total

GI-I-

canine

0 3 2 5

1 4 12 16

Total 7 14 21

Table 9. The Gingival Index for the canine.



32




The Gingival Index for the first premolar:

GI-NI-premolar

0 1 Total

GI-I-

premolar

0 3 3 6

1 3 12 15

Total 6 15 21

Table 10. The Gingival Index for the first premolar.






4.4 Pocket depth

For the pocket depth (PD) the non-parametric Wilcoxon matched-pairs signed-ranks test was

used.

Small significant differences for the pocket depth at the impaction versus the non-impaction

site can only be found at the mesiopalatal (MP) side of the canine (p=0.046) and the

distopalatal (DP) side of the lateral incisor (p=0.048) (Table 11). The pocket depth at the

impaction site was 0.43mm deeper than at the non-impaction site.

These small differences have no clinical significance.

33

MP canine

I site (mm)

MP canine

NI site (mm)

DP lat inc

I site (mm)

DP lat inc

NI site (mm)

Mean 2.76 2.33 2.76 2.33

SD 0.70 0.58 0.63 0.73

Difference 0.43 0.43

P-value 0.046 0.048

Table 11. The pocket depth (mm) at the canine and lateral incisor.

4.5 Alveolar bone height

For the alveolar bone height (AlvBH) the non-parametric Wilcoxon matched-pairs signed-

ranks test was used.

Significant differences were found for the alveolar bone height at the distal side (D) of the

lateral incisor (p=0.003), at the mesial side (M) of the canine (p<0.001) and at the distal side

of the canine (p=0.021) (Table 12). There was more bone loss on the impaction site than on

the non-impaction site varying from 0.60 to 0.85mm.

No significant differences were found at the mesial side of the first premolar.

D lat inc

I site (mm)

D lat inc

NI site

(mm)

M canine

I site (mm)

M canine

NI site

(mm)

D canine

I site (mm)

D canine

NI site

(mm)

Mean 1.66 1.06 1.90 1.05 1.76 1.16

SD 1.01 0.70 1.09 0.59 0.88 0.59

Difference 0.60 0.85 0.60

P-value 0.003 <0.001 0.021

Table 12. The alveolar bone height (mm) at the lateral incisor and canine.

4.6 Colour

Descriptive statistics were used to describe the colour agreement between the impacted and

non-impacted canines. In 10 patients (47.6%) both canines had matching colours, while in 11

patients (52.4%) both canines had a different colour.

34

4.7 Torque

For the torque differences the outcome of the normality test proved that a Paired Student’s t-

test had to be used.

No significant differences can be found for the degree of torque at the impaction versus the

non-impaction site (Table 13).

Torque I site (°) Torque NI site (°)

Mean 95.57 96.24

SD 4.30 3.47

P-value 0.515

Table 13. The torque (°) at the impaction site versus non-impaction site.

4.8 Midline deviation

Descriptive statistics were used to describe the difference in midline deviation (MDL)

between the impacted and non-impacted canines (Fig.10).

Nine patients (42.9%) had a dental midline that deviated to the impaction side; 9 patients

(42.9%) had a dental midline that deviated to the non-impaction side and 3 patients (14.3%)

had a dental midline that corresponded with the facial midline.

Figure 10. The difference in midline deviation.

MDL deviated to the NI side

MDL deviated to the I side

MDL in the middle

35

4.9 Pink Esthetic Score and Canine Esthetic Score

4.9.1 Overall score

To evaluate the overall score of the 3 dental groups descriptive statistics were used.

In general, the mean score for the PES at the impaction site was 7.58 and at the non-impaction

site 8.35 (Table14).

In general, the mean score for the CES at the impaction site is 5.93 and at the non-impaction

site 6.3 (Table 15).

According to these results, it can be concluded that the canine at the impaction site in general

had a lower score for both the PES and the CES.

4.9.2 Periodontists

To evaluate the differences concerning the PES and CES for the 3 dental groups the Wilcoxon

matched-pairs signed-ranks test was used.

For the PES, the periodontists had a mean score of 7.4 at the impaction site and 8.22 at the

non-impaction site with a statistically significant difference (p<0.001) (Table 14).

For the CES, they had a mean score of 6.00 at the impaction site and 6.31 at the non-

impaction site with a noticeable difference of 0.31 and a p-value that’s close to 0.05 but no

statistically significant difference was found (Table 15).

PES

impaction site

PES

non-impaction site

Mean SD Mean SD Level of significance P

Periodontists 7.40 1.734 8.22 1.331 <0.001

Orthodontists 7.46 1.825 8.30 1.467 <0.001

General dentists 7.87 1.956 8.52 1.547 <0.001

Overall score 7.58 1.850 8.35 1.454 /

Table 14. Differences in PES between the impaction and non-impaction site for the 3 dental groups.

36

CES

impaction site

CES

non-impaction site

Mean SD Mean SD Level of significance P

Periodontists 6.00 1.638 6.31 1.101 0.052

Orthodontists 5.97 1.480 6.34 1.196 0.008

General dentists 5.82 1.673 6.25 1.357 0.001

Overall score 5.93 1.599 6.30 1.221 /

Table 15. Differences in CES between the impaction and non-impaction site for the 3 dental groups.

4.9.3 Orthodontists

For the PES, the orthodontists had a mean score of 7.46 at the impaction site and 8.3 at the

non-impaction site with a statistically significant difference ( p<0.001) (Table 14).


impaction site with a statistically significant difference (p=0.008) (Table 15).

4.9.4 General dentists

For the PES, the general dentists had a mean score of 7.87 at the impaction site and 8.52 at the

non-impaction site with a statistically significant difference (p<0.001) (Table 14).


impaction site with a statistically significant difference (p=0.001) (Table 15).

4.9.5 Comparison between the different dental groups

To compare the repeated measurements between the different dental groups the Friedman test

was used.

4.9.5.1 PES at the impaction site

Statistically significant differences were found for the total PES score at the impaction site

between the periodontists (I_PES_TOTAL.1) and the general dentists (I_PES_TOTAL.3)

(p<0.001) and between the orthodontists (I_PES_TOTAL.2) and the general dentists

(p=0.001).

No statistical differences were found between the periodontists and the orthodontists

concerning the total PES score at the impaction site (Fig. 11).

37

Figure 11. The difference in total PES at the impaction site between the different dental groups. Each

node shows the sample average rank.

4.9.5.2 PES at the non-impaction site

At the non-impaction site only the periodontists scored significantly different from the general

dentists (p=0.019). No other statistical differences were found between the three groups.

4.9.5.3 CES at the impaction site

No statistically significant differences were found for the CES at the impaction site between

the three groups.

4.9.5.4 CES at the non-impaction site

No statistically significant differences were found for the CES at the non-impaction site

between the three groups.

4.9.6 Different parameters of the PES

To know which parameter was the most difficult to satisfy, the mean values for each

individual parameter in the three different groups were calculated (60).

ORTHO

S

PERIO

D

DENTIST

38

4.9.6.1 Periodontists

The combination of root convexity/ soft tissue colour and texture (PES_5.1) and the

parameter that focuses on the level of the soft tissue margin (PES_4.1) were the most difficult

to satisfy at both the impaction and non-impaction site within the group of periodontists. The

distal papilla (PES_2.1) was the parameter with the highest mean value (Table 16&17).

I_PES_1.1 I_PES_2.1 I_PES_3.1 I_PES_4.1 I_PES_5.1 I_PES_TOTAL.1

Mean 1,71 1,86 1,39 1,30 1,15 7,40

Std. Deviation ,49 ,36 ,66 ,72 ,67 1,73

Minimum 0 0 0 0 0 1

Maximum 2 2 2 2 2 10

Table 16. Summarized values for the PES of the periodontists at the impaction site.

NI_PES_1.1 NI_PES_2.1 NI_PES_3.1 NI_PES_4.1 NI_PES_5.1 NI_PES_TOTAL.1

Mean 1,80 1,90 1,61 1,47 1,44 8,22

Std. Deviation ,40 ,31 ,54 ,60 ,65 1,33

Minimum 1 0 0 0 0 5

Maximum 2 2 2 2 2 10

Table 17. Summarized values for the PES of the periodontists at the non-impaction site.

4.9.6.2 Orthodontists

The level of the soft tissue margin (PES_4.2) and the combination of root convexity/ soft

tissue colour and texture (PES_5.2) were the most difficult to satisfy at both the impaction

and non-impaction site within the group of orthodontists. The distal papilla (PES_2.2) was the

parameter with the highest mean value (Table 18&19).


Mean 1,66 1,86 1,44 1,23 1,27 7,46

Std. Deviation ,53 ,35 ,67 ,68 ,70 1,83

Minimum 0 1 0 0 0 1

Maximum 2 2 2 2 2 10

Table 18. Summarized values for the PES of the orthodontists at the impaction site.

39


Mean 1,79 1,94 1,65 1,40 1,52 8,30

Std. Deviation ,47 ,26 ,54 ,64 ,61 1,47

Minimum 0 0 0 0 0 2

Maximum 2 2 2 2 2 10

Table 19. Summarized values for the PES of the orthodontists at the non-impaction site.

4.9.6.3 General dentists

The level of the soft tissue margin (PES_4.3) and the combination of root convexity/ soft

tissue colour and texture (PES_5.3) were the most difficult to satisfy at both the impaction

and non-impaction site within the group of general dentists. The distal papilla (PES_2.3) was

the parameter with the highest mean value (Table 20&21).


Mean 1,71 1,83 1,52 1,39 1,42 7,87

Std. Deviation ,52 ,41 ,64 ,69 ,65 1,96

Minimum 0 0 0 0 0 0

Maximum 2 2 2 2 2 10

Table 20. Summarized values for the PES of the general dentists at the impaction site.


Mean 1,85 1,86 1,65 1,53 1,63 8,52

Std. Deviation ,39 ,40 ,56 ,59 ,57 1,55

Minimum 0 0 0 0 0 0

Maximum 2 2 2 2 2 10

Table 21. Summarized values for the PES of the general dentists at the non-impaction site.

4.9.7 Different parameters of the CES

4.9.7.1 Periodontists

The torque (CES_1.1) was the most difficult parameter to satisfy at both the impaction and

non-impaction site within the group of periodontists. The colour (CES_3.1) was the parameter

with the highest mean value (Table 22&23).

40

I_CES_1.1 I_CES_2.1 I_CES_3.1 I_CES_4.1 I_CES_TOTAL.1

Mean 1,34 1,48 1,75 1,44 6,00

Std. Deviation ,67 ,69 ,55 ,64 1,64

Minimum 0 0 0 0 1

Maximum 2 2 2 2 8

Table 22. Summarized values for the CES of the periodontists at the impaction site.

NI_CES_1.1 NI_CES_2.1 NI_CES_3.1 NI_CES_4.1 NI_CES_TOTAL.1

Mean 1,34 1,52 1,90 1,56 6,31

Std. Deviation ,68 ,60 ,30 ,62 1,10

Minimum 0 0 1 0 3

Maximum 2 2 2 2 8

Table 23. Summarized values for the CES of the periodontists at the non-impaction site.

4.9.7.2 Orthodontists


non-impaction site within the group of orthodontists. The colour (CES_3.2) was the parameter

with the highest mean value (Table 24&25).


Mean 1,33 1,48 1,69 1,46 5,97

Std. Deviation ,70 ,64 ,57 ,63 1,48

Minimum 0 0 0 0 2

Maximum 2 2 2 2 8

Table 24. Summarized values for the CES of the orthodontists at the impaction site.


Mean 1,39 1,56 1,82 1,57 6,34

Std. Deviation ,63 ,58 ,40 ,56 1,20

Minimum 0 0 0 0 2

Maximum 2 2 2 2 8

Table 25. Summarized values for the CES of the orthodontists at the non-impaction site.

41

4.9.7.3 General dentists


non-impaction site within the group of general dentists. The colour (CES_3.3) was the

parameter with the highest mean value (Table 26&27).


Mean 1,23 1,42 1,76 1,40 5,82

Std. Deviation ,77 ,67 ,55 ,73 1,67

Minimum 0 0 0 0 1

Maximum 2 2 2 2 8

Table 26. Summarized values for the CES of the general dentists at the impaction site.


Mean 1,29 1,46 1,87 1,62 6,25

Std. Deviation ,70 ,62 ,38 ,59 1,36

Minimum 0 0 0 0 2

Maximum 2 2 2 2 8

Table 27. Summarized values for the CES of the general dentists at the non-impaction site.

42

5 Discussion

5.1 Surgical exposure

In this study all patients were treated with the same surgical procedure: the open surgical

approach. Different studies have investigated the effect of the type of surgical procedure

(“open” exposure versus “radical open” exposure versus “closed” exposure) when exposing

palatally impacted canines.

Radical open exposure involves extensive bone removal around the impacted tooth’s crown to

facilitate tooth eruption. Clinical research performed over the past 30 years has demonstrated

that a radical open exposure approach is potentially harmful to the periodontal outcome of the

resolved impaction (63). Some researchers claim that exposing an impacted tooth’s CEJ

results in more recession and greater bone loss (34, 38, 64, 65). Therefore, extensive bone

removal that might involve the CEJ should be avoided (66). According to Kokich and

Mathews (67) no more than two thirds of an impacted tooth’s crown should be uncovered.

Kohavi et al. (38) examined the influence of bone removal on periodontal health. Patients

treated with more extensive bone removal such that the cemento-enamel junction was fully

exposed were compared with those patients who received less extensive bone removal where

the CEJ was not uncovered. No significant differences were found in pocket depth, Plaque

Index or Gingival Index between the 2 groups of patients. However, the authors found that

those patients treated with more extensive bone removal had on average 5.4% less bony

support than those patients treated with less extensive bone removal. The authors concluded

that exposure of the CEJ should be avoided.

Wisth et al. (68) compared “radical” surgical exposure of maxillary canines with a more

moderate exposure technique that involved flap replacement. They found that there was a

small difference between the post-treatment periodontal status of the two methods, but that

the more radical exposure technique resulted in a greater loss of bone height and greater

periodontal damage.

Those advocating the closed eruption approach site the benefits in terms of patient comfort

and long-term periodontal health.

43

The clinicians who support open exposure and spontaneous eruption of the canine argue the

advantages in terms of fewer repeated operations and the orthodontist’s ability to observe the

impacted tooth movement directly. (69, 70)

Surgically uncovering impacted teeth exposes deeper areas of the periodontium to the

destructive effects of poor plaque control. The open approach creates an atypical soft tissue

architecture that enhances plaque accumulation while challenging plaque control measures.

Routine plaque control measures must be adapted to address the exposed tooth’s atypical

position in the alveolar process and to the crater-like soft tissue defect created by an open

approach surgery. When a closed approach is used, the amount of plaque in the pericoronal

area of an impacted tooth might be reduced but plaque removal becomes impossible. (33)

The important question for the clinician is whether one of the two commonly used surgical

techniques is less harmful to long-term periodontal health. Unfortunately, a review of the

relevant literature failed to produce a clear answer to this question. Most investigations have

been limited to retrospective studies in which only one of the two surgical methods have been

evaluated (69).

Only one study performed by Wisth et al. (68) compared the periodontal health of patients

treated by the open eruption and closed eruption technique. They reported significantly deeper

mean pocket depths palatal to the previously impacted canine for those patients treated by the

closed eruption technique than those patients treated by the open eruption. Wisth et al.

explained these findings by speculating that the removal of palatal mucosa during the open

eruption technique had the same effect as a gingivectomy in reducing pocket depth. The

interdental bone levels did not differ significantly between the 2 groups. The loss of fiber

attachment on the palatal aspect was, however, greater after open surgical exposure. This may

indicate that the risk of permanent damage of the marginal periodontal fibers is greater when

this method is used. The authors concluded that the differences detected between the 2 groups

were small and the results do not support the statement that excising a wedge of palatal

mucosa when exposing a palatally impacted canine will produce a clinically significant

reduction in periodontal support.

Parkin et al. (71) performed a review of the literature concerning the use of open versus

closed surgical exposure of palatally impacted canines. This review revealed that currently,

there is no evidence to support one surgical technique over the other in terms of dental health,

aesthetics, economics and patient factors. Until high quality clinical trials with participants

44

randomly allocated into the two treatment groups are conducted, methods of exposing canines

will be left to the personal choice of the surgeon and orthodontist.

5.2 Periodontics

Several studies (35, 38, 70, 72, 73) have previously illustrated the potential problems

associated with surgical exposure and orthodontic alignment of impacted canines. However, it

must be remembered that orthodontic treatment itself carries a risk of tooth morbidity, in the

form of alveolar bone loss and loss of gingival attachment. In both situations, the role of

increased difficulty in maintaining adequate oral hygiene during appliance therapy may be

significant. (51) Orthodontic appliances complicate plaque control by interfering with

brushing, mastication and salivary flow. Additionally, the presence of orthodontic attachments

or cement irritates soft tissues. Orthodontic tooth movement in the presence of gingival

inflammation and inadequate plaque control is not recommended and can result in loss of

bone support or apical migration of gingival attachment (34, 73, 74). Impacted teeth

frequently are moved in a partially erupted state over long distances for relatively long

periods, and damage to the periodontium can occur at any time. (32)

5.2.1 Plaque and Gingival Index

In this study no statistically significant differences were found for the Plaque and Gingival

Index. Becker et al. (72) found that there were no significant differences concerning the

Plaque Index for unilateral palatally impacted canines compared to the untreated canines. By

contrast, the difference between the Gingival Index for the treated canines in relation to that

for the controls was significantly greater. The study of D’Amico et al. (75) revealed no

differences between the sides with normally erupted canines and the sides with impacted and

treated canines (closed eruption) in Plaque and Gingival index. These results were confirmed

by the studies of Quirynen et al. (76), Woloshyn et al. (77), Wisth et al. (78) and Schmidt and

Kokich (79). Hansson and Rindler (80) reported significant differences in mean Plaque Index

between treated (closed exposure) and untreated canines on the mesial and lingual aspects.

The Gingival Index did not show any difference between the treated and untreated teeth.

45

5.2.2 Pocket depth

Only small statistically significant differences were found for the pocket depth at the

distopalatal side of the lateral incisor and the mesiopalatal side of the canine in this

investigation.

The reasons for these findings can only be speculated upon and might be explained by the fact

that the palatally impacted canines had not been completely uprighted during orthodontic

treatment and thus had reached occlusion with its attachment at a more apical level.

The pocket depth differences did not exceed 0.43mm. The magnitude of the differences lacks

clinical significance. Becker et al. (72) found that the mean pocket depth at the previously

impacted canine was significantly greater than in the controls, but without any clinical

significance. By contrast, in the immediate area, the adjacent teeth showed no significant

differences in pocket depth on both treated and untreated sides. The results of Hansson and

Rindler (80) showed greater mesial probing depth of the canines on the treated side (closed

eruption), on the adjacent lateral incisors distopalatally and on the first premolars

mesiolingually. But on average none of the pocket depth differences exceeded 0.5mm.

Szarmach et al. (81) concluded that in comparison to the control group, in the orthodontically

treated group pocket depth was found to increase on the distal surfaces of the lateral incisor;

on the mesial and distal surfaces of the canine and on the mesial surfaces of the first premolar

on the treated side. Hansson and Linder-Aronson (73) and Zasciurinskiene et al. (82) found

deeper pockets on the mesial side of the treated canines, while Wisth and his co-authors (78)

found deeper pockets on the distal side. Blair et al. (51) found greater pocket depths on the

exposed canines in comparison to the contralateral unexposed canines. Woloshyn et al. (77)

found pocket depths to be significantly deeper on the mesial aspect of the previously impacted

canine than on the contralateral. Crescini et al. (66) found that at the end of follow-up the

impacted canines presented similar pocket depths when compared with the normally erupted

canines. The study of D’Amico et al. (75) revealed significant differences in pocket depth.

The pocket depth at the distobuccal surface of the impacted canines and at the mesiolingual,

distolingual, mesiobuccal and lingual surfaces of the lateral incisors was significantly deeper.

Quirynen et al. (76) reported that pocket depths on the impacted canines were slightly higher,

but the differences with the spontaneously erupted teeth did not reach statistical significance.

A closed eruption was used in the four studies mentioned above so care must be taken when

comparing these results with the results from our study that used an open exposure.

46

5.2.3 Alveolar bone height

Statistically significant changes in alveolar bone height at the impaction site occurred at the

distal side of the lateral incisor and at the mesial and distal side of the canine in this study.

The distance between the cemento-enamel junction and the crestal bone varied between 0.60

and 0.85mm and was greater at the impaction site. The error of measurement was 0.03mm.

The threshold for bone loss considered to indicate that bone loss has occurred, varies between

1 and 3mm in different studies. (41)

Nevertheless, the bone loss in our study was considered to be of permanent nature since the

patients were examined more than 1 year after completion of treatment, on average.

A possible reason for the lower bone level on the distal aspect of the adjacent lateral incisor

might be the original lingual position of the canine with its crown and follicle very close to

the root of the lateral incisor. Another explanation might be the difficulty of maintaining

proper oral hygiene in this area because appliances and attachments frequently cross the

embrasure distal to the lateral incisors during distal movement and rotation of the canines, and

this may increase the tendency for inflammation. The bone loss on the mesial surface of the

impacted canine may indicate that the bone loss was caused by the mesial pressure zone

created when the canines are uprighted in mesiodistal direction.

Becker et al. (72) expressed the bone support in percentage. They found a bony support of

89.6% in the treated teeth, in contrast to the control sides, where the canine showed 93.3%

support, representing a net loss of almost 4 percent. Hansson and Rindler (80) concluded that

the marginal bone level was significantly lower on the distal aspect both on the treated canine

(closed exposure) and on the adjacent lateral incisor. Hansson and Linder-Aronson (73) found

that changes occurred at the mesial aspects of the previously impacted canines and on the

distal aspect of the adjacent lateral incisor. These differences were small and cannot be

considered to be at a clinically significant level. Schmidt and Kokich (79) reported that crestal

bone height was lower at the mesial and distal regions of the lateral incisor adjacent to the

previously impacted canine. Wisth and colleagues (78) measured the bone loss in millimeters,

using original X-ray films. They reported a distance of 2mm from the cemento-enamel

junction to the bone margin both on the mesial and distal surfaces of the experimental canines

thus indicating a definitive bone loss. The measurement differed significantly from the control

teeth only on the mesial surface. Care must be taken when expressing the bone loss in

millimeters because this method does not express the bone loss in relation to the total tooth

47

support and, as such, is likely to introduce errors when one is comparing two teeth whose root

lengths may differ or where distortion of the radiograph may have occurred. (72) In our study,

all X-rays were calibrated using the same periodontal probe to avoid this problem.

The crestal bone height was found to be significantly lower on the mesial aspect of the

previously impacted canine and the distal surface of the adjacent lateral incisor in the study

performed by Woloshyn et al. (77). On average the distance between the cemento-enamel

junction and the mesial crestal bone was 0.52mm greater on the previously impacted canine.

The authors concluded that although statistically significant differences were detected, these

differences were small and of minor importance clinically. Quirynen et al. (76) reported a

slightly more apically located bone level around the extruded teeth when compared with the

contralateral teeth but no statistical significance was found. Zafarmand et al. (6) concluded

that the periodontal health of impacted maxillary canines that were exposed and subsequently

orthodontically aligned was acceptable. The only concern was a somewhat reduced alveolar

bone level.

5.2.4 Biotype

A negative correlation was found between the patient’s gingival biotype and the aesthetic

outcome (CES) of the previously impacted canine. Four out of the 21 patients had a thin

biotype and all four of them had a PES score above 7.5 and a CES score above 6. Despite the

statistical difference that was found for the CES, the clinical significance is negligible due to

the small sample size (underpowered). Further investigation with larger samples is needed.

Currently, no relevant literature is present to discuss this finding.

5.3 Aesthetics

As far as goes aesthetics, the results in this study indicate no difference in colour, torque or

midline deviation. The results from the CES demonstrate that all three different dental groups

found the impacted canine to be less aesthetic than the non-impacted canine. The parameter

that contributed the most to the lower score at the impaction site was the torque. Colour was

the parameter with the highest mean value. Few studies have investigated the aesthetic

outcome of previously impacted canines. Blair et al. (51) found no clinically detectable

difference in tooth colour between the exposed teeth and the control groups. The only

difference they found was that the exposed canines were incompletely erupted in comparison

48

with the controls. In our study the fourth parameter of the CES namely the ‘canine cusp’ also

scored lower in the three different dental groups when comparing the exposed canine with the

non-exposed canine. D’ Amico et al. (75) evaluated the tooth colour, tooth shape, tooth

position and tooth inclination of previously impacted maxillary canines. No significant

differences concerning the colour, shape and position could be seen between the groups. The

only statistically significant difference they found was for the inclination: 80% of the

normally erupted canines had a normal inclination, whereas only 57% of the previously

impacted canines had a normal inclination after treatment. Ling et al. (83) investigated the

canine position, dental midline and canine colour. They found no significant differences in

midline deviation nor colour. They did found that the previously impacted canines were more

intruded after treatment and this finding was statistically significant. Woloshyn et al. (77)

concluded that approximately 40% of the previously impacted canines exhibited noticeable

relapse and were judged to be intruded, lingually displaced, mesially rotated, as well as

discoloured. Schmidt and Kokich (79) stated that the three most common reasons given for

identifying the previously impacted canines are torque, gingiva and alignment. Differences in

torque reflect the difficulty in moving the rooth of the treated canine buccally enough with

orthodontic appliances to mimic the contralateral canine eminence. Gingiva indicates a

perceived difference in amount of attached gingiva when compared with the contralateral

tooth, or a difference in the relative heights of the gingival margins. Alignment reflects either

a tendency towards relapse of the treated canine or a lack of complete alignment of the

impacted canine after orthodontic treatment.

5.4 Radiographic assessment

The pre-treatment radiographic parameters (α-angle, d-distance and s-sector) did not have an

influence on and the periodontal and/or aesthetic outcome of the previously impacted canines.

Crescini et al. (52) evaluated the prognostic role of the pre-treatment radiographic features on

the post-treatment periodontal status of intra-osseous impacted maxillary canines. They

concluded that these parameters measured on the pre-treatment radiograph did not represent

valid prognostic indicators of final periodontal status of impacted canines treated by the

combined surgical-orthodontic approach. Similar results were reported by Quirynen et al. (76)

and by Nieri et al. (84). Only one article written by Zasciurinskiene et al. (82) found that

periodontal conditions of the impacted canine and adjacent teeth after surgical-orthodontic

49

treatment depend on the initial vertical and horizontal position of the impacted canine. They

found that the pocket depth at the incisor distopalatally was greater in the group of impacted

canines with an initial higher vertical position. This suggests that the periodontal tissue of the

adjacent teeth undergoes increased stress during canine extrusion. The horizontal position of

the impacted canine was also found to affect pocket depth. Pocket depths were greater at the

mesiobuccal side of the incisor and at the mesiobuccal, buccal and distobuccal side of the first

premolar in the canines that were situated closer to the dental midline. These findings cannot

be supported by our study.

Ferguson et al. (39) concluded that the radiographic position is of limited value in predicting

the behaviour of the canine following exposure. The only influence the pre-treatment

parameters have, is on the duration of treatment. This finding is supported by several authors

(84-87).

5.5 PES and CES evaluation by different dental groups

In this study both the overall score and the individual scores of the three different dental

groups clearly indicated that the previously impacted canine could always be identified by

scoring both the PES and the CES. The periodontists had a tendency to score lower for the

PES which can be explained by the fact that they are more critical as far as goes periodontal

health because of their daily clinical experience. For the CES no differences were found

between the three groups. In the literature no articles could be found that use the PES for

scoring the gingival outcome of previously impacted canines. Since the CES is a new method

for scoring the aesthetic outcome, no articles could be found using this method. Some articles,

however, did investigate whether it was possible to identify which of the maxillary canines

had been impacted previously. D’ Amico et al. (75) concluded that 61% of the originally

palatally impacted canines could by identified by five orthodontists. When these orthodontists

evaluated colour slides of the patients, they judged 56% to have a good aesthetic result. In the

study of Ling et al. (83) both assessors correctly identified 86% of the previously impacted

maxillary canines. Schmidt (79) and Woloshyn (77) both found that the treated canine could

be visually identified from the untreated canine in 70 to 80% of the cases.

Further research is needed to compare the outcome of the PES and CES overall and in the

three different dental groups in this study.

50

5.6 Critical evaluation

Attention should be brought upon the fact that this study was performed at a University

setting with different clinicians treating patients. However, these clinicians were all trained by

the same supervisors who all carry the same treatment philosophy in order to give an

unambiguous education. The same remark could be made for the maxillofacial surgeons that

performed the canine exposure. Initially a power calculation was done, but unfortunately we

didn’t succeed to reach the number of patients indicated by the power calculation so further

research with larger samples is needed to draw a conclusive connection between impacted

canines and their periodontal health and aesthetics.

51

6 Conclusion

There were no significant differences in the different measured parameters between

the impacted and non-impacted canines, except for the alveolar bone height.

In the different dental groups the overall rating scores for the PES and CES were

lower for the impacted canines.

With a carefully planned interdisciplinary cooperation, a combined surgical-

orthodontic approach in treatment of impacted maxillary canines produces clinically

acceptable periodontal and aesthetic conditions.

52

7 References

1. Kasander T. The impacted canine: diagnosis and treatment. J Clin Orthod. 1994;5:13-21.

2. Gron AM. Prediction of tooth emergence. J Dent Res. 1962;41:573-85. 3. Bishara SE. Clinical management of impacted maxillary canines. Semin

Orthod. 1998 Jun;4(2):87-98. PubMed PMID: 9680907. Epub 1998/07/29. eng. 4. Karpagam S, Chacko RK. Guidelines for management of impacted canines.

Indian J Dent Res. 2004;15:48-53. 5. Dewel BF. The upper cuspid: Its development and impaction. Angle Orthod.

1949;19:79-90. 6. Zafarmand AH, Gholami GA. Evalution of the periodontal status of palatally

impacted maxillary canines after exposure using a modified window technique. World J Orthod. 2009 Winter;10(4):295-300. PubMed PMID: 20072745. Epub 2010/01/15. eng.

7. Shapira Y, Kuftinec MM. Early diagnosis and interpretation of potential maxillary canine impaction. J Am Dent Assoc. 1998;129:1450-54.

8. D'Amico RM BK, Kurol J, Falahat B. Long-term results of orthodontic treatment of impacted maxillary canines. Angle Orthod. 2003;73(231-8).

9. Thilander B, Jakobsson SO. Local factors in impaction of maxillary canines. Acta Odontol Scand. 1968;26:145-68.

10. Rayne J. The unerupted maxillary canine. Dent Pract Dent Rec. 1969;19:194-204.

11. Bass TB. Observations on the misplaced upper canine tooth. Dent Pract Dent Rec. 1967;18:25-33.

12. Bishara SE. Impacted maxillary canines: a review. Am J Orthod Dentofacial Orthop. 1992 Feb;101(2):159-71. PubMed PMID: 1739070. Epub 1992/02/01. eng.

13. Pecks S, Peck L, Kataja M. The palatally displaced canine as a dental anomaly of genetic origin. Angle Orthod. 1994;64:249-56.

14. Bishara SE, Kommer DD, Mcneil MH. Management of impacted canines. Am J Orthod. 1976;80:173-90.

15. Moyers RE. Handbook of Orthodontics (ed 2). Chicago, IL: Year Book Medical Publishers; 1963.

16. Jacoby H. The etiology of maxillary canine impaction. Am J Orthod. 1983;84:125-32.

17. Miller BH. Influence of congenitally missing teeth on the eruption of upper canine. Trans Br Soc Study Orhtod. 1963;50:17-24.

18. Becker A, Smith P, Behar R. The incidence of anomalous lateral incisors in relation to palatally displaced cuspids. Angle Orthod. 1981;51:24-9.

19. Becker A. In defense of the guidance theory of palatal canine displacement. . Angle Orthod. 1995;65:95-8.

20. Shafer WG, Hine MK, Levy BM. A textbook of Oral pathology (ed 2). Philadelphia, PA: Saunders; 1963.

21. Becker A. The orthodontic treatment of impacted teeth. United Kingdom: Martin Dunitz; 1998.

53

22. Clarck CA. A method of ascertaining the relative position of unerupted teeth by means of film radiographs. Proc R Soc Med Odontol Sectn. 1910;3:87-90.

23. Caminiti MF, Sandor GK, Giambattistini C, Tompson B. Outcomes of the surgical exposure, bonding and eruption of 82 impacted maxillary canines. J Can Dent Assoc. 1998 Sep;64(8):572-4, 6-9. PubMed PMID: 9785687. Epub 1998/10/24. eng.

24. Ericson S, Kurol J. Diagnosis of ectopically erupting maxillary canines – A case report. Eur J Orthod. 1988;10:115.

25. Williams BH. Diagnosis and prevention of maxillary cuspid impaction. Angle Orthod. 1981;51:30-40.

26. Ericson S, Kurol J. Early treatment of palatally erupting maxillary canines by extraction of the primary canines. Eur J Orthod. 1988;10:283-95.

27. Kallu R, Vincker F, Politis C, Mwalili S, Willems G. Tooth transplantations: a descriptive retrospective study. International Journal of Maxillofacial Surgery. 2005;34:745-55.

28. Kim E, Jung JY, Chai IH, Kun KY, Lee SJ. Evaluation of the prognosis and causes of failure of 182 cases of autogenous tooth transplantation. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology & Endodontics. 2005;100:112-9.

29. Kristerson L. Autotransplantation of human premolars. A clinical and radiographic study of 100 teeth. International Journal of Oral Surgery. 1985;14:200-13.

30. McSherry P. The ectopic maxillary canine: a review. British Journal of Orthodontics. 1998;25:209-16.

31. Thomas S, Turner SR, Sandy JR. Autotransplantation of teeth: Is there a role? British Journal of Orthodontics. 1998;25:275-82.

32. Frank C. Periodontal concerns associated with the orthodontic treatment of impacted teeth. American Journal of Orthodontics and Dentofacial Orthopedics. 2002;121(6):639-49.

33. Frank CA, Long M. Periodontal concerns associated with the orthodontic treatment of impacted teeth. Am J Orthod Dentofacial Orthop. 2002 Jun;121(6):639-49. PubMed PMID: 12080317. Epub 2002/06/25. eng.

34. Vanarsdall R, Corn H. Soft tissue management of labially positioned unerupted teeth. Am J Orthod. 1977;72:53-64.

35. Wisth PJ, Norderval K, Boe OE. Comparison of two surgical methods in combined surgical-orthodontic correction of impacted maxillary canines. Acta Odontol Scand. 1976;34:53-7.

36. Boyd RL. Clinical assessment of injuries in orthodontic movement of impacted teeth. I. Methods of attachment. Am J Orthod. 1982 Dec;82(6):478-86. PubMed PMID: 6760724. Epub 1982/12/01. eng.

37. Tegsjo U, Valerius-Olsson H, Andersson L. Periodontal conditions follwing surgical exposure of unerupted maxillary canines- a long term follow-up study of two surgical techniques. Swed Dent J. 1984;8:257-63.

38. Kohavi D, Becker A, Zilberman Y. Surgical exposure, orthodontic movement, and final tooth position as factors in periodontal breakdown of treated palatally impacted canines. American journal of orthodontics. 1984 Jan;85(1):72-7. PubMed PMID: 6581728. Epub 1984/01/01. eng.

54

39. Ferguson JW, Parvizi F. Eruption of palatal canines following surgical exposure: a review of outcomes in a series of consecutively treated cases. British Journal of Orthodontics. 1997;24:203-7.

40. Iramaneerat S, Cunningham SJ, Horrocks EN. The effect of two alternative methods of canine exposure upon subsequent duration of orthodontic treatment. International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children. 1998 Jun;8(2):123-9. PubMed PMID: 9728097. Epub 1998/09/05. eng.

41. Lindhe JK, T.; Lang, N.P. Clinical Periodontology and Implant Dentistry. Munksgaard B, editor2003.

42. Loe H. The Gingival Index, the Plaque Index and the Retention Index Systems. Journal of periodontology. 1967 Nov-Dec;38(6):Suppl:610-6. PubMed PMID: 5237684. Epub 1967/11/01. eng.

43. Loe H, Silness J. Periodontal disease in pregnancy. I. Prevalence and severity. Acta Odontol Scand. 1963 Dec;21:533-51. PubMed PMID: 14121956. Epub 1963/12/01. eng.

44. Ainamo J, Bay I. Problems and proposals for recording gingivitis and plaque. International dental journal. 1975 Dec;25(4):229-35. PubMed PMID: 1058834. Epub 1975/12/01. eng.

45. Muhlemann HR SS. Gingival sulcus bleeding-aleading symptom in initial gingivitis. Helv Odontol Acta. 1971;15:107-13.

46. Ericson I, Thilander B. Peridontal conditions after orthodontic tooth movements in the dog Angle Orthod. 1978;48:210-8.

47. Ericson I, Thilander B. Orthodontic forces and recurrence of periodontal disease. Am J Orthod. 1978;74:41-50.

48. Sinclair PM, Berry CW, Bennett CL, Israelson H. Changes in gingiva and gingival flora with bonding and banding. Angle Orthod. 1987;57:271-8.

49. Polson AM. Interrelationships of inflammation and tooth mobility (trauma) in pathogenesis of peridontal disease. J Clin Periodontol. 1980;7:351-60.

50. Kohavi D, Zilberman Y, Becker A. Periodontal status following the alignment of buccally ectopic maxillary canine teeth. Am J Orthod. 1984;85:78-82.

51. Blair GS, Hobson RS, Leggat TG. Posttreatment assessment of surgically exposed and orthodontically aligned impacted maxillary canines. Am J Orthod Dentofacial Orthop. 1998 Mar;113(3):329-32. PubMed PMID: 9517726. Epub 1998/03/28. eng.

52. Crescini A, Nieri M, Buti J, Baccetti T, Pini Prato GP. Pre-treatment radiographic features for the periodontal prognosis of treated impacted canines. J Clin Periodontol. 2007 Jul;34(7):581-7. PubMed PMID: 17555411. Epub 2007/06/09. eng.

53. Crescini A, Nieri M, Buti J, Baccetti T, Pini Prato GP. Orthodontic and periodontal outcomes of treated impacted maxillary canines. Angle Orthod. 2007 Jul;77(4):571-7. PubMed PMID: 17605500. Epub 2007/07/04. eng.

54. Pontoriero R, Carnevale G. Surgical crown lengthening: a 12-month clinical wound healing study. Journal of periodontology. 2001 Jul;72(7):841-8. PubMed PMID: 11495130. Epub 2001/08/10. eng.

55. Anderegg CR, Metzler DG, Nicoll BK. Gingiva thickness in guided tissue regeneration and associated recession at facial furcation defects. Journal of

55

periodontology. 1995 May;66(5):397-402. PubMed PMID: 7623260. Epub 1995/05/01. eng.

56. Baldi C, Pini-Prato G, Pagliaro U, Nieri M, Saletta D, Muzzi L, et al. Coronally advanced flap procedure for root coverage. Is flap thickness a relevant predictor to achieve root coverage? A 19-case series. Journal of periodontology. 1999 Sep;70(9):1077-84. PubMed PMID: 10505811. Epub 1999/10/03. eng.

57. Eghbali A, De Rouck T, De Bruyn H, Cosyn J. The gingival biotype assessed by experienced and inexperienced clinicians. J Clin Periodontol. 2009 Nov;36(11):958-63. PubMed PMID: 19811580. Epub 2009/10/09. eng.

58. Kan JY, Rungcharassaeng K, Umezu K, Kois JC. Dimensions of peri-implant mucosa: an evaluation of maxillary anterior single implants in humans. Journal of periodontology. 2003 Apr;74(4):557-62. PubMed PMID: 12747463. Epub 2003/05/16. eng.

59. De Rouck T, Eghbali R, Collys K, De Bruyn H, Cosyn J. The gingival biotype revisited: transparency of the periodontal probe through the gingival margin as a method to discriminate thin from thick gingiva. J Clin Periodontol. 2009 May;36(5):428-33. PubMed PMID: 19419444. Epub 2009/05/08. eng.

60. Belser UC, Grutter L, Vailati F, Bornstein MM, Weber HP, Buser D. Outcome evaluation of early placed maxillary anterior single-tooth implants using objective esthetic criteria: a cross-sectional, retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores. Journal of periodontology. 2009 Jan;80(1):140-51. PubMed PMID: 19228100. Epub 2009/02/21. eng.

61. Andrews LF. The six keys to normal occlusion. Am J Orthod. 1972 Sep;62(3):296-309. PubMed PMID: 4505873. Epub 1972/09/01. eng.

62. Fleiss JL. Analysis of data from multiclinic trials. Controlled clinical trials. 1986 Dec;7(4):267-75. PubMed PMID: 3802849. Epub 1986/12/01. eng.

63. Becker A, Casap N, Chaushu S. Conventional wisdom and the surgical exposure of impacted teeth. Orthodontics & craniofacial research. 2009 May;12(2):82-93. PubMed PMID: 19419451. Epub 2009/05/08. eng.

64. Bishara SE. Impacted maxillary canines: a review. American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 1992 Feb;101(2):159-71. PubMed PMID: 1739070. Epub 1992/02/01. eng.

65. Boyd RL. Clinical assessment of injuries in orthodontic movement of impacted teeth. II. Surgical recommendations. American journal of orthodontics. 1984 Nov;86(5):407-18. PubMed PMID: 6594063. Epub 1984/11/01. eng.

66. Crescini A, Nieri M, Buti J, Baccetti T, Mauro S, Prato GP. Short- and long-term periodontal evaluation of impacted canines treated with a closed surgical-orthodontic approach. J Clin Periodontol. 2007 Mar;34(3):232-42. PubMed PMID: 17257160. Epub 2007/01/30. eng.

67. Kokich V, Mathews D. Surgical-orthodontic management of impacted teeth. Dent Clin North Am. 1993;37:181-204.

68. Wisth PJ, Norderval K, Booe OE. Comparison of two surgical methods in combined surgical-orthodontic correction of impacted maxillary canines. Acta

56

odontologica Scandinavica. 1976;34(1):53-7. PubMed PMID: 1066949. Epub 1976/01/01. eng.

69. Burden DJ, Mullally BH, Robinson SN. Palatally ectopic canines: Closed eruption versus open eruption. American Journal of Orthodontics and Dentofacial Orthopedics. 1999 Jun;115(6):640-4. PubMed PMID: WOS:000080894500008.

70. Wisth PJ, Norderval K, Boe OE. Periodontal status of orthodontically treated impacted maxillary canines. Angle Orthod. 1976 Jan;46(1):69-76. PubMed PMID: 1062179. Epub 1976/01/01. eng.

71. Parkin N, Benson PE, Thind B, Shah A. Open versus closed surgical exposure of canine teeth that are displaced in the roof of the mouth. Cochrane Database of Systematic Reviews. 2008 (4). PubMed PMID: WOS:000259895000081.

72. Becker A, Kohavi D, Zilberman Y. Periodontal status following the alignment of palatally impacted canine teeth. Am J Orthod. 1983 Oct;84(4):332-6. PubMed PMID: 6578683. Epub 1983/10/01. eng.

73. Hansson C, Linder-Aronson S. Gingival status after orthodontic treatment of impacted upper canines. Transactions European Orthodontic Society. 1972:433-41. PubMed PMID: 4523553. Epub 1972/01/01. eng.

74. Wise RJ. Periodontal diagnosis and management of the impacted maxillary cuspid. The International journal of periodontics & restorative dentistry. 1981;1(2):56-73. PubMed PMID: 6954139. Epub 1981/01/01. eng.

75. D'Amico RM, Bjerklin K, Kurol J, Falahat B. Long-term results of orthodontic treatment of impacted maxillary canines. Angle Orthod. 2003 Jun;73(3):231-8. PubMed PMID: 12828430. Epub 2003/06/28. eng.

76. Quirynen M, Op Heij DG, Adriansens A, Opdebeeck HM, van Steenberghe D. Periodontal health of orthodontically extruded impacted teeth. A split-mouth, long-term clinical evaluation. Journal of periodontology. 2000 Nov;71(11):1708-14. PubMed PMID: 11128918. Epub 2000/12/29. eng.

77. Woloshyn H, Artun J, Kennedy DB, Joondeph DR. Pulpal and periodontal reactions to orthodontic alignment of palatally impacted canines. Angle Orthod. 1994;64(4):257-64. PubMed PMID: 7978520. Epub 1994/01/01. eng.

78. Wisth PJ, Norderval K, Boe OE. Periodontal status of orthodontically treated impacted maxillary canines. Angle Orthod. 1976 Jan;46(1):69-76. PubMed PMID: 1062179. Epub 1976/01/01. eng.

79. Schmidt AD, Kokich VG. Periodontal response to early uncovering, autonomous eruption, and orthodontic alignment of palatally impacted maxillary canines. Am J Orthod Dentofacial Orthop. 2007 Apr;131(4):449-55. PubMed PMID: 17418710. Epub 2007/04/10. eng.

80. Hansson C, Rindler A. Periodontal conditions following surgical and orthodontic treatment of palatally impacted maxillary canines--a follow-up study. Angle Orthod. 1998 Apr;68(2):167-72. PubMed PMID: 9564427. Epub 1998/06/20. eng.

81. Szarmach IJ, Szarmach J, Waszkiel D, Paniczko A. Assessment of periodontal status following the alignment of impacted permanent maxillary canine teeth. Adv Med Sci. 2006;51 Suppl 1:204-9. PubMed PMID: 17458091. Epub 2007/04/27. eng.

82. Zasciurinskiene E, Bjerklin K, Smailiene D, Sidlauskas A, Puisys A. Initial vertical and horizontal position of palatally impacted maxillary canine and effect

57

on periodontal status following surgical-orthodontic treatment. Angle Orthod. 2008 Mar;78(2):275-80. PubMed PMID: 18251594. Epub 2008/02/07. eng.

83. Ling KK, Ho CT, Kravchuk O, Olive RJ. Comparison of surgical and non-surgical methods of treating palatally impacted canines. II. Aesthetic outcomes. Aust Orthod J. 2007 May;23(1):8-15. PubMed PMID: 17679529. Epub 2007/08/08. eng.

84. Nieri M, Crescini A, Rotundo R, Baccetti T, Cortellini P, Pini Prato GP. Factors affecting the clinical approach to impacted maxillary canines: A Bayesian network analysis. Am J Orthod Dentofacial Orthop. 2010 Jun;137(6):755-62. PubMed PMID: 20685530. Epub 2010/08/06. eng.

85. Crescini A, Nieri M, Buti J, Baccetti T, Pini Prato GP. Orthodontic and periodontal outcomes of treated impacted maxillary canines. Angle Orthod. 2007 Jul;77(4):571-7. PubMed PMID: 17605500. Epub 2007/07/04. eng.

86. Fleming PS, Scott P, Heidari N, Dibiase AT. Influence of radiographic position of ectopic canines on the duration of orthodontic treatment. Angle Orthod. 2009 May;79(3):442-6. PubMed PMID: 19413390. Epub 2009/05/06. eng.

87. Stewart JAH, G.; Glover, K.E.; Williamson, P.C.; Lam, E.W.; Major, P.W. Factors that relate to treatment duration for patients with palatally impacted maxillary canines. Am J Orthod Dentofacial Orthop. 2001;119:216-25.

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Appendix 1

Informatiebrief voor de deelnemers onder de 18 jaar

Titel van de studie:

Het resultaat van hoektanden met een oorspronkelijke slechte positie die met een beugel op de

juiste plaats zijn gezet.

Doel van de studie:

Men heeft u gevraagd om deel te nemen aan een studie.

Waarom doen we deze studie?

We willen hoektanden met een oorspronkelijke slechte positie bestuderen nadat ze met een

beugel op de juiste plaats zijn gezet. Bij elke hoektand zal er worden gekeken hoe mooi de

tand staat in de tandenrij samen met het tandvlees er rond.

Beschrijving van de studie:

De hoektand is een belangrijke tand in de tandenrij. Hoektanden met een slechte positie zijn

dus een probleem voor de patiënt en daar moet best iets aan gedaan worden. De hoektand in

de tandenrij brengen is niet gemakkelijk voor de tandarts en daarom willen wij bij zoveel

mogelijk patiënten het resultaat hiervan bekijken.

Om het resultaat te bestuderen, moeten we de nodige informatie verzamelen (zie procedures)

Het verzamelen van deze informatie zal ongeveer 1uur duren.

Wat wordt verwacht van de deelnemer?

Voor het welslagen van de studie, is het uitermate belangrijk dat u volledig meewerkt met de

onderzoeker en dat zijn/haar instructies nauwlettend worden opgevolgd.

Bovendien moet u onderstaande items respecteren:

Voor het welslagen van de studie is het belangrijk dat u de toestemming geeft om

bovenstaande gegevens te verzamelen.

Deelname en beëindiging:

De deelname aan deze studie vindt plaats op vrijwillige basis.

Deelname aan deze studie brengt voor u geen onmiddellijk therapeutisch voordeel. De

deelname in de studie kan helpen om in de toekomst patiënten beter te kunnen helpen.

U kan weigeren om deel te laten nemen aan de studie en u kan zich op elk ogenblik

terugtrekken uit de studie zonder dat u hiervoor een reden moet opgeven en zonder dat dit op

Appendix 1

enigerlei wijze een invloed zal hebben op de verdere relatie en/of behandeling met de

onderzoeker of de behandelende arts.

De deelname aan deze studie zal worden beëindigd als de onderzoeker meent dat dit in uw

belang is. U kan ook voortijdig uit de studie worden teruggetrokken als u de in deze

informatiebrief beschreven procedures niet goed opvolgt of de beschreven items niet

respecteert.

Als u deelneemt, wordt u en uw ouder(s)/voogd gevraagd het toestemmingsformulier te

tekenen.

Procedures:

Volgend materiaal zal op éénzelfde afspraak worden verzameld:

Afdrukken van de boven- en ondertandboog

Foto’s van de tanden en van het gezicht

Metingen van het tandvlees

Metingen van de plaque (= het vuil) op de tanden

Metingen van het tandvlees indien het bloedt

Een kleine röntgenfoto van de hoektand links en rechts

Kleurmeting van de hoektand links en rechts

Studieverloop:

De afspraak is éénmalig en duurt ongeveer 1 uur.

Risico’s en voordelen:

Voordelen

Het experiment zal geen onmiddellijk voordeel aan de onderzochte brengen.

Deze studie maakt deel uit van een geheel van onderzoeken waarvan het diagnostisch of

therapeutisch belang niet onmiddellijk duidelijk is, maar waarvan mag verwacht worden dat

de resultaten later tot een betere kennis van de therapeutische toepassingen van ingesloten

hoektanden zullen leiden.

Risico’s

Er zijn geen gekende risico’s voor de onderzochte.

Als er in het verloop van de studie gegevens aan het licht komen die een invloed zouden

kunnen hebben op uw bereidheid om te blijven deelnemen aan deze studie, zult u daarvan op

de hoogte worden gebracht. Mocht u door uw deelname toch enig nadeel ondervinden, zal u

een gepaste behandeling krijgen.

Appendix 1

Deze studie werd goedgekeurd door een onafhankelijke Commissie voor Medische Ethiek

verbonden aan het UZ Gent en wordt uitgevoerd volgens de richtlijnen voor de goede

klinische praktijk (ICH/GCP) en de verklaring van Helsinki opgesteld ter bescherming van

mensen deelnemend aan klinische studies. In geen geval dient u de goedkeuring door de

Commissie voor Medische Ethiek te beschouwen als een aanzet tot deelname aan deze studie.

Kosten:

De deelname aan deze studie brengt geen extra kosten mee voor u.

Vergoeding:

U zal niet vergoed worden voor uw deelname aan deze studie.

Vertrouwelijkheid:

In overeenstemming met de Belgische wet van 8 december 1992 en de Belgische wet van 22

augustus 2002, zal u persoonlijke levenssfeer worden gerespecteerd en zal u toegang krijgen

tot de verzamelde gegevens. Elk onjuist gegeven kan op uw verzoek verbeterd worden.

Vertegenwoordigers van de opdrachtgever, auditoren, de Commissie voor Medische Ethiek en

de bevoegde overheden hebben rechtstreeks toegang tot uw tandheelkundig dossiers om de

procedures van de studie en/of de gegevens te controleren, zonder de vertrouwelijkheid te

schenden. Dit kan enkel binnen de grenzen die door de betreffende wetten zijn toegestaan.

Door het toestemmingsformulier, na voorafgaande uitleg, te ondertekenen stemt u in met deze

toegang.

Als u akkoord gaat om aan deze studie deel te nemen, zullen u persoonlijke en

tandheelkundige gegevens tijdens deze studie worden verzameld en gecodeerd (hierbij kan

men uw gegevens nog terug koppelen naar uw persoonlijk dossier). Verslagen waarin u wordt

geïdentificeerd, zullen niet openlijk beschikbaar zijn. Als de resultaten van de studie worden

gepubliceerd, zal uw identiteit vertrouwelijke informatie blijven.

Letsels ten gevolge van deelname aan de studie:

De onderzoeker voorziet in een vergoeding en/of medische behandeling in het geval van

schade en/of letsel tengevolge van deelname aan de studie. Voor dit doeleinde is een

verzekering afgesloten met foutloze aansprakelijkheid conform de wet inzake experimenten

Appendix 1

op de menselijke persoon van 7 mei 2004. Op dat ogenblik kunnen uw gegevens doorgegeven

worden aan de verzekeraar.

Contactpersoon:

Als er een letsel optreedt tengevolge van de studie, of als u aanvullende informatie wenst over

de studie of over uw rechten en plichten, kunt u in de loop van de studie op elk ogenblik

contact opnemen met:

Stéphanie Eeckhout in opdracht van Prof. Dr. G. De Pauw

09/332.68.93 09/332.59.23

[email protected] [email protected]

Appendix 1

Toestemmingsformulier

Ik, _________________________________________ heb het document “Informatiebrief

voor de deelnemers aan experimenten” pagina 1 tot en met 4 gelezen en er een kopij van

gekregen. Ik stem in met de inhoud van het document en stem ook in deel te nemen aan de

studie.

Ik heb een kopij gekregen van dit ondertekende en gedateerde formulier voor

“Toestemmingsformulier”. Ik heb uitleg gekregen over de aard, het doel, de duur, en de te

voorziene effecten van de studie en over wat men van mij verwacht. Ik heb uitleg gekregen

over de mogelijke risico’s en voordelen van de studie. Men heeft me de gelegenheid en

voldoende tijd gegeven om vragen te stellen over de studie, en ik heb op al mijn vragen een

bevredigend antwoord gekregen.

Ik stem ermee in om volledig samen te werken met de toeziende onderzoeker. Ik zal hem/haar

op de hoogte brengen als ik onverwachte of ongebruikelijke symptomen ervaar.

Men heeft mij ingelicht over het bestaan van een verzekeringspolis in geval er letsel zou

ontstaan dat aan de studieprocedures is toe te schrijven.

Ik ben me ervan bewust dat deze studie werd goedgekeurd door een onafhankelijke

Commissie voor Medische Ethiek verbonden aan het UZ Gent en dat deze studie zal

uitgevoerd worden volgens de richtlijnen voor de goede klinische praktijk (ICH/GCP) en de

verklaring van Helsinki, opgesteld ter bescherming van mensen deelnemend aan

experimenten. Deze goedkeuring was in geen geval de aanzet om te beslissen om deel te

nemen aan deze studie.

Ik mag me op elk ogenblik uit de studie terugtrekken zonder een reden voor deze beslissing

op te geven en zonder dat dit op enigerlei wijze een invloed zal hebben op mijn verdere relatie

met de onderzoeker.

Appendix 1

Men heeft mij ingelicht dat de gegevens worden verwerkt en bewaard gedurende minstens 20

jaar. Ik stem hiermee in en ben op de hoogte dat ik recht heb op toegang en verbetering van

deze gegevens. Aangezien deze gegevens verwerkt worden in het kader van medisch-

wetenschappelijke doeleinden, begrijp ik dat de toegang tot mijn gegevens kan uitgesteld

worden tot na beëindiging van het onderzoek. Indien ik toegang wil tot mijn gegevens, zal ik

mij richten tot de toeziende onderzoeker, die verantwoordelijk is voor de verwerking.

Ik begrijp dat auditors, vertegenwoordigers van de opdrachtgever, de Commissie voor

Medische Ethiek of bevoegde overheden, mijn gegevens mogelijk willen inspecteren om de

verzamelde informatie te controleren. Door dit document te ondertekenen, geef ik

toestemming voor deze controle. Bovendien ben ik op de hoogte dat bepaalde gegevens

doorgegeven worden aan de opdrachtgever. Ik geef hiervoor mijn toestemming, zelfs indien

dit betekent dat mijn gegevens doorgegeven worden aan een land buiten de Europese Unie.

Ten alle tijden zal mijn privacy gerespecteerd worden.

Appendix 1

Ik ben bereid op vrijwillige basis mijn kind te laten deelnemen aan deze studie.

Naam van de vrijwilliger + ouders/voogd: ________________________________

Datum: ________________________________

Handtekening vrijwilliger + ouders/voogd:

Ik bevestig dat ik de aard, het doel, en de te voorziene effecten van de studie heb uitgelegd

aan de bovenvermelde vrijwilliger.

De vrijwilliger stemde toe om deel te nemen door zijn/haar persoonlijk gedateerde

handtekening te plaatsen.

Naam van de persoon

die voorafgaande uitleg

heeft gegeven: _________________________________________

Datum: _________________________________________

Handtekening:

Appendix 2

Informatiebrief voor de deelnemers boven de 18 jaar

Titel van de studie:

Het resultaat van hoektanden met een oorspronkelijke slechte positie die met een beugel op de

juiste plaats zijn gezet.

Doel van de studie:

Men heeft u gevraagd om deel te nemen aan een studie.

Waarom doen we deze studie?

We willen hoektanden met een oorspronkelijke slechte positie bestuderen nadat ze met een

beugel op de juiste plaats zijn gezet. Bij elke hoektand zal er worden gekeken hoe mooi de

tand staat in de tandenrij samen met het tandvlees er rond.

Beschrijving van de studie:

De hoektand is een belangrijke tand in de tandenrij. Hoektanden met een slechte positie zijn

dus een probleem voor de patiënt en daar moet best iets aan gedaan worden. De hoektand in

de tandenrij brengen is niet gemakkelijk voor de tandarts en daarom willen wij bij zoveel

mogelijk patiënten het resultaat hiervan bekijken.

Om het resultaat te bestuderen, moeten we de nodige informatie verzamelen (zie procedures)

Het verzamelen van deze informatie zal ongeveer 1uur duren.

Wat wordt verwacht van de deelnemer?

Voor het welslagen van de studie, is het uitermate belangrijk dat u volledig meewerkt met de

onderzoeker en dat u zijn/haar instructies nauwlettend opvolgt. Bovendien moet u

onderstaande items respecteren: Voor het welslagen van de studie is het belangrijk dat u de

toestemming geeft om bovenstaande gegevens te verzamelen.

Deelname en beëindiging:

De deelname aan deze studie vindt plaats op vrijwillige basis.

Deelname aan deze studie brengt voor u geen onmiddellijk therapeutisch voordeel. Uw

deelname in de studie kan helpen om in de toekomst patiënten beter te kunnen helpen.

Appendix 2

U kan weigeren om deel te nemen aan de studie, en u kunt zich op elk ogenblik terugtrekken

uit de studie zonder dat u hiervoor een reden moet opgeven en zonder dat dit op enigerlei

wijze een invloed zal hebben op uw verdere relatie en/of behandeling met de onderzoeker of

de behandelende arts.

Uw deelname aan deze studie zal worden beëindigd als de onderzoeker meent dat dit in uw

belang is. U kunt ook voortijdig uit de studie worden teruggetrokken als u de in deze

informatiebrief beschreven procedures niet goed opvolgt of u de beschreven items niet

respecteert.

Als u deelneemt, wordt u gevraagd het toestemmingsformulier te tekenen.

Procedures:

Volgend materiaal zal op éénzelfde afspraak worden verzameld:

Afdrukken van de boven- en ondertandboog

Foto’s van de tanden en van het gezicht

Metingen van het tandvlees

Metingen van de plaque (= het vuil) op de tanden

Metingen van het tandvlees indien het bloedt

Een kleine röntgenfoto van de hoektand links en rechts

Kleurmeting van de hoektand links en rechts

Studieverloop:

De afspraak is éénmalig en duurt ongeveer 1 uur.

Risico’s en voordelen:

Voordelen

Het experiment zal geen onmiddellijk voordeel aan de onderzochte brengen.

Deze studie maakt deel uit van een geheel van onderzoeken waarvan het diagnostisch of

therapeutisch belang niet onmiddellijk duidelijk is, maar waarvan mag verwacht worden dat

de resultaten later tot een betere kennis van de therapeutische toepassingen van ingesloten

hoektanden zullen leiden.

Risico’s

Er zijn geen gekende risico’s voor de onderzochte.

Appendix 2

Als er in het verloop van de studie gegevens aan het licht komen die een invloed zouden

kunnen hebben op uw bereidheid om te blijven deelnemen aan deze studie, zult u daarvan op

de hoogte worden gebracht. Mocht u door uw deelname toch enig nadeel ondervinden, zal u

een gepaste behandeling krijgen.

Deze studie werd goedgekeurd door een onafhankelijke Commissie voor Medische Ethiek

verbonden aan het UZ Gent en wordt uitgevoerd volgens de richtlijnen voor de goede

klinische praktijk (ICH/GCP) en de verklaring van Helsinki opgesteld ter bescherming van

mensen deelnemend aan klinische studies. In geen geval dient u de goedkeuring door de

Commissie voor Medische Ethiek te beschouwen als een aanzet tot deelname aan deze studie.

Kosten:

De deelname aan deze studie brengt geen extra kosten mee voor U.

Vergoeding:

U zal niet vergoed worden voor uw deelname aan deze studie.

Vertrouwelijkheid:

In overeenstemming met de Belgische wet van 8 december 1992 en de Belgische wet van 22

augustus 2002, zal u persoonlijke levenssfeer worden gerespecteerd en zal u toegang krijgen

tot de verzamelde gegevens. Elk onjuist gegeven kan op uw verzoek verbeterd worden.

Vertegenwoordigers van de opdrachtgever, auditoren, de Commissie voor Medische Ethiek en

de bevoegde overheden hebben rechtstreeks toegang tot Uw tandheelkundig dossier om de

procedures van de studie en/of de gegevens te controleren, zonder de vertrouwelijkheid te

schenden. Dit kan enkel binnen de grenzen die door de betreffende wetten zijn toegestaan.

Door het toestemmingsformulier, na voorafgaande uitleg, te ondertekenen stemt U in met

deze toegang.

Als u akkoord gaat om aan deze studie deel te nemen, zullen uw persoonlijke en

tandheelkundige gegevens tijdens deze studie worden verzameld en gecodeerd (hierbij kan

men uw gegevens nog terug koppelen naar uw persoonlijk dossier). Verslagen waarin U

wordt geïdentificeerd, zullen niet openlijk beschikbaar zijn. Als de resultaten van de studie

worden gepubliceerd, zal uw identiteit vertrouwelijke informatie blijven.

Letsels ten gevolge van deelname aan de studie:

Appendix 2

De onderzoeker voorziet in een vergoeding en/of medische behandeling in het geval van

schade en/of letsel tengevolge van deelname aan de studie. Voor dit doeleinde is een

verzekering afgesloten met foutloze aansprakelijkheid conform de wet inzake experimenten

op de menselijke persoon van 7 mei 2004. Op dat ogenblik kunnen uw gegevens doorgegeven

worden aan de verzekeraar.

Contactpersoon:

Als er een letsel optreedt tengevolge van de studie, of als U aanvullende informatie wenst

over de studie of over uw rechten en plichten, kunt U in de loop van de studie op elk ogenblik

contact opnemen met:

Stéphanie Eeckhout in opdracht van Prof. Dr. G. De Pauw

09/332.68.93 09/332.59.23

[email protected] [email protected]

Appendix 2

Toestemmingsformulier

Ik, _________________________________________ heb het document “Informatiebrief

voor de deelnemers aan experimenten” pagina 1 tot en met 4 gelezen en er een kopij van

gekregen. Ik stem in met de inhoud van het document en stem ook in deel te nemen aan de

studie.

Ik heb een kopij gekregen van dit ondertekende en gedateerde formulier voor

“Toestemmingsformulier”. Ik heb uitleg gekregen over de aard, het doel, de duur, en de te

voorziene effecten van de studie en over wat men van mij verwacht. Ik heb uitleg gekregen

over de mogelijke risico’s en voordelen van de studie. Men heeft me de gelegenheid en

voldoende tijd gegeven om vragen te stellen over de studie, en ik heb op al mijn vragen een

bevredigend antwoord gekregen.

Ik stem ermee in om volledig samen te werken met de toeziende onderzoeker. Ik zal hem/haar

op de hoogte brengen als ik onverwachte of ongebruikelijke symptomen ervaar.

Men heeft mij ingelicht over het bestaan van een verzekeringspolis in geval er letsel zou

ontstaan dat aan de studieprocedures is toe te schrijven.

Ik ben me ervan bewust dat deze studie werd goedgekeurd door een onafhankelijke

Commissie voor Medische Ethiek verbonden aan het UZ Gent en dat deze studie

zal uitgevoerd worden volgens de richtlijnen voor de goede klinische praktijk (ICH/GCP) en

de verklaring van Helsinki, opgesteld ter bescherming van mensen deelnemend aan

experimenten. Deze goedkeuring was in geen geval de aanzet om te beslissen om deel te

nemen aan deze studie.

Ik mag me op elk ogenblik uit de studie terugtrekken zonder een reden voor deze beslissing

op te geven en zonder dat dit op enigerlei wijze een invloed zal hebben op mijn verdere relatie

met de onderzoeker.

Men heeft mij ingelicht dat de gegevens worden verwerkt en bewaard gedurende minstens 20

jaar. Ik stem hiermee in en ben op de hoogte dat ik recht heb op toegang en verbetering van

Appendix 2

deze gegevens. Aangezien deze gegevens verwerkt worden in het kader van medisch-

wetenschappelijke doeleinden, begrijp ik dat de toegang tot mijn gegevens kan uitgesteld

worden tot na beëindiging van het onderzoek. Indien ik toegang wil tot mijn gegevens, zal ik

mij richten tot de toeziende onderzoeker, die verantwoordelijk is voor de verwerking.

Ik begrijp dat auditors, vertegenwoordigers van de opdrachtgever, de Commissie voor

Medische Ethiek of bevoegde overheden, mijn gegevens mogelijk willen inspecteren om de

verzamelde informatie te controleren. Door dit document te ondertekenen, geef ik

toestemming voor deze controle. Bovendien ben ik op de hoogte dat bepaalde gegevens

doorgegeven worden aan de opdrachtgever. Ik geef hiervoor mijn toestemming, zelfs indien

dit betekent dat mijn gegevens doorgegeven worden aan een land buiten de Europese Unie.

Ten alle tijden zal mijn privacy gerespecteerd worden.

Appendix 2

Ik ben bereid op vrijwillige basis deel te nemen aan deze studie.

Naam van de vrijwilliger: _________________________________________

Datum: _________________________________________

Handtekening:

Ik bevestig dat ik de aard, het doel, en de te voorziene effecten van de studie heb uitgelegd

aan de bovenvermelde vrijwilliger.

De vrijwilliger stemde toe om deel te nemen door zijn/haar persoonlijk gedateerde

handtekening te plaatsen.

Naam van de persoon

die voorafgaande uitleg

heeft gegeven: _________________________________________

Datum: _________________________________________

Handtekening:

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