La résorption des incisives maxillaires après traitement orthodontique – étude clinique des facteurs de risque

Ó 2015 CEO Published by / E´dite´ par Elsevier Masson SAS All rights reserved / Tous droits re´serve´s

Original Article Article original

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors
sorption des incisives maxillaires apre s La re
tude clinique des traitement orthodontique – e facteurs de risque Rajae ELHADDAOUIa,*, Hicham BENYAHIAa, Mohamed-Faouzi AZEROUALa, Fatima ZAOUIa, Rachid RAZINEb, Loubna BAHIJEa a

Facult
e de m
edecine dentaire, universit
e Mohammed V Souissi-Rabat, avenue Mohamed El Jazouli, BP 6212, Rabat, Morocco b Laboratoire de biostatistique de recherche clinique et d’
epid
emiologie (LBRCE), facult
e de m
edecine et de pharmacie, universit
e Mohammed V Souissi-Rabat, avenue Mohamed El Jazouli, BP 6203, Rabat, Morocco Available online: 27 January 2016 / Disponible en ligne : 27 janvier 2016

Summary


sume
Re

Introduction: External apical root resorption (EARR) is one of the major problems associated with orthodontic treatment. Such lesions represent an iatrogenic risk that must be detected as early as possible, with regular radiological follow-up and appropriate therapeutic precautions. The causes and mechanisms leading to susceptibility to root resorption following the application of an orthodontic force are often not clear and are generally said to be of multifactorial origin. The aim of this clinical study was to analyze the factors linked to the occurrence of moderate to severe resorption (MSR) of upper incisors during orthodontic treatment in a group of Moroccan patients treated in the Dento-Facial Orthopedic Department of the Dental Consultation and Treatment Center (Centre de consultation et de traitements dentaires [CCTD]) in Rabat.


Introduction : Les resorptions radiculaires apicales externes  (RRAE) constituent l’un des problemes majeurs du traitement

 orthodontique. Ces lesions representent un risque iatrogene ^ decel
e
le plus tot ^ possible, faire non intentionnel qui doit etre
 et de precautions
l’objet de surveillance radiologique reguli ere

eralement,

therapeutiques. Gen les causes et mecanismes
intervenant dans la susceptibilite
a` la resorption radiculaire suite a` l’application d’une force orthodontique ne sont pas ^ d’une origine multifactorielle. Cette clairs et on parle plutot

etude clinique avait pour objectif d’analyser les facteurs lies

ees
a` sev
eres  a` la survenue des resorptions moder (RMS) des incisives maxillaires durant le traitement orthodontique,
chez une population marocaine traitee au service
d’orthopedie dentofaciale au Centre de consultation et de traitements dentaires (CCTD) de Rabat.

Materiel et methode : Un total de 82 patients (28 hommes, ^ es
de 12 a` 27 ans, presentant

72 femmes) ag differentes mal
e
traitees
a` l’aide d’appareils fixes occlusions qui avaient et pendant au moins 1 an, et qui avaient des radiographies
panoramiques au debut, en cours et a` la fin de traitement,
e
selectionn

au hasard. La reduction
ont et es de la longueur
e
evalu

en se des racines des incisives maxillaires a et ee

Material and methods: A total of 82 patients (28% males, 72% females) aged between 12 and 27, with various malocclusions, who had been treated with fixed appliances for at least 1 year and for whom panoramic X-rays at the start, during and at the end of treatment were available, were selected randomly. The reduction in maxillary incisor root length was evaluated using resorption scores. The factors studied in relation to the risk of

Correspondence and reprints / Correspondance et tire
s a` part. e-mail address / Adresse e-mail : [email protected] (Rajae Elhaddaoui) *

48

International Orthodontics 2016 ; 14 : 48-64 http://dx.doi.org/10.1016/j.ortho.2015.12.015

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors


sorption des incisives maxillaires apre s traitement orthodontique – e
tude clinique des facteurs de risque La re

Ó 2015 CEO. Published by Elsevier Masson SAS. All rights reserved


basant sur des scores de resorption. Les facteurs dont on a
etudi e
l’association avec le risque de survenue des RMS
^
de traitement, l’extraction etaient : l’age, le sexe, la duree ou la non extraction, le type de malocclusion (Classe I DDM, Classe II, Classe III), le diagnostic vertical (normal, supraclu

sie, beance), la presence de dysfonctions, l’inclusion canine
e
et la morphologie radiculaire. L’analyse statistique a et
ee
par le logiciel SPSS version 18.0, les tests statisrealis
sont : la methode
 tiques utilises de Kaplan-Meier et le modele
de Cox univarie
et multivarie
pour l’etude des facteurs
aux RMS. Le degre
de significativite
a et
e
fixe
associes a` 0,05.


de fa¸c on statisResultats : Les facteurs qui etaient associes tiquement significative au risque de survenue des RMS au niveau des incisives maxillaires sont : le type de dents avec
e
pour l’incisive laterale
un risque plus elev (HR = 3,2 IC 95 % [2,3–4,5] p < 0,001), les traitements avec extractions
(HR = 1,64 IC 95 % [1,16–2,33] p < 0.05), la presence de supraclusie (HR = 2,17 IC 95 % [1,33–3,53] p < 0,05) ou de
beance (HR = 3,12 IC 95 % [1,66–5,86] p < 0,001) et la dysmorphie radiculaire (HR = 1,5 IC 95 % [1,09–2,07] p < 0,05). ^
de traitement, le type de malocclusion, L’age, le sexe, la duree

de les dysfonctions et l’inclusion canine n’etaient pas associes fa¸c on statistiquement significative au risque de survenue des RMS des incisives maxillaires.
^ de Conclusion : Les RRAE sont difficilement evitables, le role l’orthodontiste reste crucial pour identifier les facteurs de ris

que, afin d’adapter la strategie therapeutique en fonction de ces facteurs. Dans notre population, le risque de RMS des incisives maxillaires augmenterait dans les cas avec extrac

tions, les cas de supraclusie et de beance et en presence d’anomalies radiculaires. En dernier lieu, des recommanda
tions cliniques pour prevenir la survenue de RMS au niveau des incisives maxillaires et qui tiennent compte de l’ensemble
e
enonc

des facteurs de risque ont et ees. Ó 2015 CEO. E´dite´ par Elsevier Masson SAS. Tous droits re´serve´s

Key-words


s Mots-cle

occurrence of MSR were: age, sex, treatment duration, extraction or non-extraction, type of malocclusion (Class I archlength discrepancy, Class II, Class III), the vertical diagnosis (normal, supraocclusion, open bite), presence of dysfunction, impacted canines and root morphology. Statistical analysis was performed using SPSS software, version 18.0. Statistical tests used were: Kaplan-Meier analysis and the univariate and multivariate Cox models for the study of factors associated with MSR. The threshold of significance adopted was 0.05.

Results: The factors that were significantly associated with the occurrence of MSR at the level of the upper incisors were: tooth type, with a greater risk for the lateral incisor (HR = 3.2 95% CI [2.3–4.5] P < 0.001), treatments with extraction (HR = 1.64 95% CI [1.16–2.33] P < 0.05), the presence of supraocclusion (HR = 2.17 95% CI [1.33–3.53] P < 0.05) or open bite (HR = 3.12 95% CI [1.66–5.86] P < 0.001) and root malformation (HR = 1.5 95% CI [1.09–2.07] P < 0.05). Age, sex, type of malocclusion, dysfunction and impaction of canines were not associated at a statistically significant level with the risk of occurrence of MSR of the upper incisors. Conclusion: EARR is difficult to avoid; the orthodontist’s role remains crucial in identifying risk factors so as to adopt a treatment strategy taking these factors into account. In our population, the risk of MSR in the upper incisors appeared to increase in treatments with extraction, situations of supraocclusion or open bite, and in the presence of root abnormalities. Finally, clinical recommendations for the prevention of the occurrence of MSR of the maxillary incisors are proposed, taking into account all the risk factors identified.

·· ··

Root resorption. Severity. Maxillary incisor. Orthodontic treatment.

·· ··


sorption radiculaire. Re
ve
rite
. Se Incisive maxillaire. Traitement orthodontique.

Introduction

Introduction

External apical root resorption (EARR) of orthodontic origin is an unwanted iatrogenic consequence frequently associated with orthodontic treatment. Various studies [1–7] have reported prevalence rates for EARR ranging between 65.6% and 98%.


sorptions radiculaires apicales externes (RRAE) d’oriLes re
quence iatroge
nique gine orthodontique constituent la conse
e aux the
rapeunon intentionnelle, constamment associe
rentes e
tudes [1–7] ont tiques orthodontiques. En effet, diffe
une pre
valence des RRAE qui variait de 65,6 % rapporte a` 98 %.

International Orthodontics 2016 ; 14 : 48-64

49

Rajae ELHADDAOUI et al.

According to Harry and Sims [4], most cases of EARR are mild and clinically insignificant. However, when there is moderate resorption limited to one third of the apex, and more particularly in cases of severe resorption affecting more than one third of root length, the longevity of the dentition and, consequently, the stability of the orthodontic treatment could be at risk. The etiology and mechanisms of action of EARR of orthodontic origin are not entirely clear [8]; several studies [1–4,9–12] have suggested a multifactorial etiology involving both individual factors (age, systemic disease, individual susceptibility, root morphology, genetic factors, etc.) and factors inherent to the orthodontic treatment (duration, extractions, type of appliance, force applied, amplitude of movement, etc.). The aim of this study was first to describe the prevalence of EARR at the level of the upper incisors and secondly to report on the incidence of moderate to severe resorptions (MSR) in this group of teeth and to analyze the contribution of general and therapeutic risks factors to the occurrence of this resorption.


des RRAE sont le
ge  res et Selon Harry et Sims [4], la majorite cliniquement insignifiantes, alors que dans les cas de
sorptions mode
re
es confine
es au tiers de l’apex, ou partire rement dans les cas de re
sorptions se
ve res de
passant le culie
vite
du syste me tiers apical de la longueur radiculaire, la longe
quent, la stabilite
du traitement orthodondentaire et par conse tique seraient compromises.
tiologie et le me
canisme d’action des RRAE d’origine orthoL’e rement e
lucide
s [8] ; plusieurs dontique ne sont pas entie
tudes [1–4,9–12] ont e
voque
une e
tiologie multifactorielle e ^ge, maladies faisant appel a` des facteurs individuels (a
miques, susceptibilite
individuelle, morphologie radicusyste
ne
tiques. . .) ainsi qu’a` des facteurs inhe
rents laire, facteurs ge
e de traitement, les au traitement orthodontique (la dure
e, l’ampliextractions, le type d’appareillage, la force applique
placement. . .). Le but de la pre
sente e
tude e
tait tude de de
crire la pre
valence des RRAE dans un premier temps de de me au niveau des incisives maxillaires, et dans un deuxie
sorptions mode
re
es temps, de rapporter l’incidence des re
ve res (RMS) au niveau de ce groupe de dents, ainsi que a` se
ne
raux et the
rapeula contribution des facteurs de risque ge
sorptions. tiques dans la survenue de ces re

Materials and methods


riels et me
thodes Mate

The sample


chantillon L’e

The files of 350 patients were consulted; these are subjects who finished a course of orthodontic treatment between 2003 and 2014 at the Dento-Facial Orthopedic Department of the Dental Consultation and Treatment Center (Centre de consultation et de traitements dentaires [CCTD]) in Rabat. The study concerned 318 teeth in 82 randomly selected patients who met the following inclusion criteria: age  12 years, minimum duration of multi-bracket treatment: 12 months, with complete radiological work-up before, during and after treatment. Exclusion criteria were as follows: patients suffering from systemic diseases (diabetes, osteoarthritis, hypothyroidism, etc.), labio-alveolar-palatal clefts, previous traumatic episodes, periodontal disease, immature incisors, endodontically-treated teeth, cases of bruxism and orthodontic-surgical cases.


te
consulte
s, il s’agit des Les dossiers de 350 patients ont e
leur traitement orthodontique entre 2003 sujets ayant acheve et 2014 au Centre de consultation et de traitements dentaires
tude a concerne
318 dents chez (CCTD) de Rabat. L’e
lectionne
s au hasard, ayant satisfait aux 82 patients se res d’inclusion suivants : a ^ge  12 ans, dure
e minimale crite du traitement multi-attache de 12 mois, avec un bilan radiologique complet avant, au cours et a` la fin de traitement. res d’exclusion e
taient les suivants : les patients Les crite
sentant des maladies syste
miques (diabe te, arthrose, pre
olo-palatines, des hypothyroı¨die. . .), des fentes labio-alve
ce
dents de traumatisme ante
rieur, des parodontopathies, ante
es endodontiquedes incisives immatures, des dents traite ment, les cas de bruxisme et les cas orthodonticochirurgicaux.

The variables

Les variables

In the selected patient files, the following factors were examined so as to identify a possible association with the occurrence of MSR: age, sex, treatment duration, type of treatment (with or without extractions), the type of malocclusion (Class 1 arch-length discrepancy, Class II, Class III), the vertical diagnosis (normal, supraocclusion, open bite), swallowing dysfunction, impacted canines and root morphology (normal, or root abnormality).


te
examine
s afin de relever les Les dossiers retenus ont e
tudie
l’association avec la survenue de facteurs dont on a e ^ge, le sexe, la dure
e de traitement, le type de RMS, a` savoir : l’a traitement (avec ou sans extractions), le type de malocclusion (Classe I DDM, Classe II, Classe III), le diagnostic occlusal
ance), la de
glutition dysfoncvertical (normal, supraclusie, be tionnelle, l’inclusion canine et la morphologie radiculaire (normale, anomalie radiculaire).

50

International Orthodontics 2016 ; 14 : 48-64

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors


sorption des incisives maxillaires apre s traitement orthodontique – e
tude clinique des facteurs de risque La re

[(Fig._1)TD$IG]

Fig. 1: Classification of root morphology abnormalities according to Levander and Malmgren (1998) [13]. Fig. 1 : Classification des anomalies de la morphologie radiculaire selon Levander et Malmgren (1998) [13].

The aim was to determine retrospectively the time to occurrence of MSR. For this purpose: — the period of evaluation of SRs extended from the date of start of treatment to the date of end of treatment; — the period of evaluation of MSRs extended from the date of start of treatment to the date of the panorex on which these resorptions were visible W 6 months (fig. 3).


but de traitement a e
te
La radiographie panoramique du de
e pour l’e
tude des anomalies de la morphologie radicuutilise laire en se basant sur la classification de Levander et Malmgren (1998) [13] (fig. 1).
es au cours et a` la Les radiographies panoramiques demande
te
examine
es pour fin du traitement orthodontique ont e
valuation des RRAE, en se re
fe
rant aux scores de la classil’e fication de Levander et Malmgren (1998) [14] (fig. 2).
sentant des RRAE, elles ont e
te
divise
es en Pour les dents pre
ve
rite
de la re
sorption : les 2 sous-groupes selon la se
sorptions le
ge  res (RL), et les re
sorptions mode
re
es re
ve res (RMS). a` se
tait de de
terminer de manie re re
trospective le de
lai de Le but e survenue des RMS, pour cela :
lai d’e
valuation des RL s’e
tendait de la date du de
but — le de de traitement a` la date de fin de traitement ;
lai d’e
valuation des RMS s’e
tendait de la date du de
but — le de de traitement a` la date de la radiographie panoramique ou` ces
sorptions e
taient visibles W 6 mois (fig. 3). re

Statistical analysis

L’analyse statistique

Descriptive: to describe the characteristics of the sample the quantitative variables were expressed as mean W standard deviation, and the qualitative variables were expressed as number and percentage. Analytical: the occurrence of MSR was studied using the Kaplan-Meier method. The characteristics of the MSR group and the SR group were compared by means of the Log Rank test. Factors associated with MSR were studied using the Cox univariate and multivariate models. The multivariate model comprised the variables which were associated at a statistically significant level, or with P < 0.30 in the univariate analysis. The significance level adopted was 0.05.


crire les caracte
ristiques de l’e
chantillon, Descriptive : pour de
es les variables quantitatives sont exprime en
cart-type et les variables qualitatives sont moyenne W e
es en effectif et pourcentage. exprime
tude de la survenue des RMS a e
te
re
alise
e par Analytique : l’e
thode de Kaplan-Meier. Nous avons compare
le groupe la me
rentes avec RMS et le groupe avec RL concernant les diffe
ristiques par le test de Log Rank. L’e
tude des facteurs caracte
s aux RMS a e
te
re
alise
e par le mode le de Cox uniassocie
et multivarie
. Le mode le multivarie
ae
te
constitue
par les varie
taient associe
es de fa¸con statistiquement sigvariables qui e
e. Le degre
nificative, ou avec un p < 0,30 en analyse univarie
ae
te
fixe
a` 0,05. de significativite

The start of treatment panorex was used for the study of root morphology abnormalities, based on the Levander and Malmgren classification (1998) [13] (fig. 1). Root resorption was evaluated using the panoramic X-rays obtained during and at the end of treatment, with reference to the scores of the Levander and Malmgren classification (1998) [14] (fig. 2). Teeth showing signs of EARR were divided into 2 sub-groups according to the severity of resorption: slight resorption (SR) and moderate to severe resorption (MSR).

International Orthodontics 2016 ; 14 : 48-64

51

Rajae ELHADDAOUI et al.

[(Fig._2)TD$IG]

Fig. 2: Stages of EARRs according to the classification of Levander and Malmgren (1998) [14]. Score 0: regular root outline; score 1: slight resorption, the outline of the apex is diffuse, softened (< 2 mm); score 2: moderate resorption (> 2 mm), the outline of the apex is discontinuous (1/2 circle), resorption is limited to the apical third; score 3: severe resorption, the outline of the apex is very irregular, resorption extends beyond the apical third. Fig. 2 : Stades des RRAE selon la Classification de Levander et Malmgren (1998) [14]. Score 0 : contour radi
gulier ; score 1 : re
sorption le
ge  re, le contour de culaire re
mousse
(< 2 mm) ; score 2 : re
sorption l’apex est diffus/e
re
e (> 2 mm), le contour de l’apex est discontinu (demi mode
sorption est confine
e a` un tiers apical ; score 3 : cercle), la re
sorption se
ve  re, le contour de l’apex est tre s irre
gulier, la re
sorption de
passe le tiers de l’apex. re

Results


sultats Re

The characteristics of the study population are presented in Table I. Females were predominant in our sample (72%) compared to males (28%); ages varied between 12 and 27 with an average of 16.8 W 4.3 years, while the average duration of treatment was 30.7 W 10.7 months. Treatments with and without extractions were almost equivalent in number, 52.4% and 47.6%, respectively.


chantillon : les caracte
ristiques de Description de l’e
chantillon sont pre
sente
es dans le Tableau I. l’e
minin e
tait pre
dominant dans notre e
chantillon Le sexe fe ^ge variait de (72 %) par rapport au sexe masculin (28 %), l’a
e 12 a` 27 ans, avec une moyenne de 16,8 W 4,3 ans et la dure
tait de 30,7 W 10,7 mois. Les traitemoyenne de traitement e
taient re
alise
s presque selon la ments avec extractions e ^me fre
quence que les traitements sans extractions me (52,4 % et 47,6 % respectivement).

[(Fig._3)TD$IG]

Fig. 3: Method of evaluation of time to occurrence of MSR.
thode d’e
valuation du de
lai de survenue des RMS. Fig. 3 : Me

52

International Orthodontics 2016 ; 14 : 48-64

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors


sorption des incisives maxillaires apre s traitement orthodontique – e
tude clinique des facteurs de risque La re

Table I Characteristics of the sample.

Variables / Variables
a Age (years) / Aˆge (annees) Sex / Sexeb Male / Masculin
Female / Feminin Type of teeth / Type de dentsb Central / Centrale
Lateral / Laterale
de traitement (mois)a Treatment duration (months) / Duree Type of treatment / Type de traitementb Non-extraction / Sans extractions Extraction / Avec extractions Type of malocclusion / Type de malocclusionsb Class I ALD / Classe I DDM Class II / Classe II Class III / Classe III Vertical diagnosis / Diagnostic verticalb Normal / Normal Overbite / Supraclusie
Open bite / Beance Dysfunctions / Dysfonctionsb No / Non
Dysfunctional swallowing / Deglutition dysfonctionnelle b Impacted canine / Canine incluse No / Non Yes / Oui Root morphology / Morphologie radiculaireb Normal / Normale Root anomaly / Anomalie radiculaire a b

Tableau I


ristiques de l’e
chantillon. Caracte

Values / Valeurs 16.8 W 4.3 29 (28) 236 (72) 164 (50) 164 (50) 30.7 W 10.7 156 (47.6) 172 (52.4) 188 (64.4) 88 (30.1) 16 (5.5) 96 (29.3) 152 (46.3) 80 (24.4) 164 (50) 164 (50) 288 (87.8) 40 (12.2) 160 (50.3) 158 (49.7)

Expressed as mean W standard deviation / Exprim
e en moyenne W
ecart-type. Expressed as actual and percentage / Exprim
e en effectif et pourcentage.

Class I ALD was the most frequent (64.4%), followed by Class II (30.1%), while Class III represented only 5.5% of malocclusions. Supraocclusion was predominant, with a frequency of 46.3%, while open bite cases represented 24.4%. Swallowing dysfunction was present in 50% of cases, and there were 12.2% of impacted canines. The frequency of roots with abnormalities was almost identical to that of roots without (49.7% and 50.3%, respectively). When comparing the two incisors (Table II), the presence of root abnormalities was greater in the lateral, essentially on account of the presence of short roots (22.2%), apical hook (24.1%) and thin roots (12%), compared with the central

International Orthodontics 2016 ; 14 : 48-64


tait plus fre
quente (64,4 %), suivie de la La classe I DDM e
sentait que 5,5 % des classe II (30,1 %), la classe III ne repre
tait pre
dominante avec une malocclusions. La supraclusie e
quence de 46,3 %, alors que les cas de be
ance repre
senfre
glutition dysfonctionnelle taient 24,4 %. Les cas de de
sentaient 50 %, et l’inclusion canine e
tait note
e dans repre
quence des racines avec anomalies radiculaires 12,2 %. La fre
tait presque e
gale a` celle des racines sans anomalies radie culaires (49,7 % et 50,3 % respectivement).
sence En comparant les deux incisives (Tableau II), la pre
tait plus pre
dominante pour l’incid’anomalies radiculaires e
rale, essentiellement par la fre
quence importante des sive late
s (24,1 %) et gre ^ les racines courtes (22,2 %), des apex coude

53

Rajae ELHADDAOUI et al.

Table II

Tableau II

Description of the root morphology according to the type of teeth.

Description de la morphologie radiculaire selon le type de dents.

Root morphology / Morphologie radiculaire Actual (%) / Effectif (%) Tooth / Dent

Normal /

Short root /

Normale

Racine courte

Blunt apex /


Apex emouss e


Central / Centrale

96 (60)

10 (6.3)

33 (20.6)


Lateral / Laterale

64 (40.5)

35 (22.2)

5 (3.2)

incisor, with 6.3%, 5% and 8.1%, respectively. This difference was statistically significant (P < 0.001). The prevalence of EARR in our sample was 95%. In total, 35.7% were slight resorptions (score 1), 40.3% were moderate (score 2), while severe resorptions (score 3) represented 19% (Table III). Incidence of moderate and severe resorptions (MSR): — overall incidence: at 18 months, the estimated incidence of MSR was 10%, at 24 months it was 31%, and 70% of MSR occurred at 36 months and beyond (fig. 4); — incidence of MSR depending on the different variables: in general, and for all the variables, the incidence of MSR increased over time, from 18 to 24 months and then to 36 months. The incidence of MSR increased more significantly between 24 months and 36 months (12-month interval) than between 18 months and 24 months (6-month interval) (Table IV). The incidence of MSR was higher among males (75.2%) than females (67.4%). According to tooth type, the incidence of MSR was higher for lateral incisors (82.5%).

Table III Prevalence of EARR.

Angled apex /

Small apex /

8 (5)

13 (8.1)

Apex coude


38 (24.1)

^ Apex grele

0.001

19 (12)

(12 %), comparativement a` l’incisive centrale (6,3 %, 5 % et
rence e
tait statistiquement 8,1 % respectivement). Cette diffe significative (p < 0,001).
valence des RRAE dans notre e
chantillon e
tait de 95 %. La pre
taient des re
sorptions le
ge  res (score 1), Au total, 35,7 % e
taient des re
sorptions mode
re
es (score 2), alors 40,3 % e
sorptions se
ve res (score 3) repre
sentaient 19 % que les re (Tableau III).
sorptions mode
re
es a` se
ve res (RMS) : Incidence des re
te
— incidence globale : a` 18 mois ; l’incidence des RMS a e
e a` 10 %, a` 24 mois, cette incidence e
tait de 31 %, estime alors que 70 % des RMS ont survenu a` partir de 36 mois (fig. 4) ;
rentes variables : d’une — incidence des RMS selon les diffe re ge
ne
rale, et pour toutes les variables, l’incidence des manie RMS augmentait avec le temps, en allant de 18 mois a` 24 mois, puis a` 36 mois. L’incidence des RMS augmentait
e de 24 mois a` 36 mois (12 mois de fa¸con plus marque d’intervalle) que de 18 mois a` 24 mois (6 mois d’intervalle) (Tableau IV).
tait plus importante chez le sexe masL’incidence des RMS e
minin (67,4 %). Selon le culin (75,2 %), que chez le sexe fe
tait plus e
leve
e pour type de dents, l’incidence des RMS e
rale (82,5 %). l’incisive late

Tableau III


valence des RRAE. Pre


Resorption stage / Stade de resorption
Absence of resorption (score 0) / Absence de resorption (score 0)

 Mild resorption (score 1) / Resorption legere (score 1)

ee
(score 2) Moderate resorption (score 2) / Resorption moder

ere  (score 3) Severe resorption (score 3) / Resorption sev

54

P/p

Values / Valeurs Actual (%) / Effectif (%) 16 (5) 113 (35.7) 128 (40.3) 61 (19)

International Orthodontics 2016 ; 14 : 48-64

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors


sorption des incisives maxillaires apre s traitement orthodontique – e
tude clinique des facteurs de risque La re

[(Fig._4)TD$IG]

Fig. 4: Curve of occurrence of MSR. Fig. 4 : Courbe de survenue des RMS.

Concerning the other variables, the incidence of MSR was also higher in cases with extractions (80%), class II malocclusions (78%), supraocclusion (76%) and open bite (80%), and in the presence of swallowing dysfunction (77.4%) and root dysmorphism (71.6%). Factors associated with MSR: when the contribution of each factor was evaluated independently of the others by univariate analysis, the factors significantly associated with the risk of occurrence of MSR were: tooth type, with a higher risk for the lateral incisor (P < 0.001), treatments with extractions (P < 0.001), supraocclusion (P < 0.001) and open bite (P < 0.001), swallowing dysfunction (P < 0.05) and abnormal root morphology (P < 0.05). The aim of multivariate analysis is to study the contribution of all factors simultaneously. The variables entered into the multivariate model were those significantly associated with MSR, or having a P-value < 0.30 in univariate analysis. In multivariate analysis (Table V), and adjusting for all variables, the factors that were associated with the occurrence of MSR at a statistically significant level are: tooth type, with a higher risk for the lateral incisor (HR = 3.2 95% CI [2.3–4.5] P < 0.001), treatment with extractions (HR = 1.64 95% CI [1.16–2.33] P < 0.05), the presence of open bite (HR = 3.12 95% CI [1.66–5.86] P < 0.001) or supraocclusion (HR = 2.17 95% CI [1.33–3.53] P < 0.05) and root dysmorphism (HR = 1.5 95% CI [1.09–2.07] P < 0.05) (Table VI). In our study, the risk of occurrence of MSR was multiplied by: — 3 for the lateral incisor (95% CI [2.3–4.5] P < 0.001); — 1.64 for cases with extractions (95% CI [1.16–2.33] P < 0.05); — 2 for cases of supraocclusion (95% CI [1.33–3.53] P < 0.05); International Orthodontics 2016 ; 14 : 48-64


tait e
galement Pour les autres variables, l’incidence des RMS e plus importante dans les cas avec extractions (80 %), les malocclusions de classe II (78 %), les cas de supraclusie
ance (80 %), les cas de de
glutition dysfonc(76 %) et de be tionnelle (77,4 %) et de dysmorphie radiculaire (71,6 %).
s aux RMS : en e
valuant la contribution Les facteurs associe
pendamment des autres par analyse de chaque facteur inde
e, les facteurs significativement associe
s au risque de univarie
taient : le type de dents avec un risque survenue des RMS e
leve
pour l’incisive late
rale (p < 0,001), les traitements plus e avec extractions (p < 0,001), la supraclusie (p < 0,001) et la
ance (p < 0,001), la de
glutition dysfonctionnelle (p < 0,05) be et la morphologie radiculaire anormale (p < 0,05).
e vise a` e
tudier la contribution de tous les L’analyse multivarie
ment. Les variables introduites dans le facteurs simultane le multivarie
e
taient associe
es de fa¸con statistiquement mode
e. significative ou avec un p < 0,30 en analyse univarie
e (Tableau V) et en ajustant sur toutes En analyse multivarie
taient associe
s de fa¸con statisles variables, les facteurs qui e tiquement significative au risque de survenue des RMS sont :
leve
pour l’incisive le type de dents avec un risque plus e
rale (HR = 3,2 IC 95 % [2,3–4,5] p < 0,001), les traitelate ments avec extractions (HR = 1,64 IC 95 % [1,16–2,33]
sence de be
ance (HR = 3,12 IC 95 % [1,66– p < 0,05), la pre 5,86] p < 0,001) ou de supraclusie (HR = 2,17 IC 95 % [1,33– 3,53] p < 0,05) et la dysmorphie radiculaire (HR = 1,5 IC 95 % [1,09–2,07] p < 0,05) (Tableau VI).
tude, le risque de survenue des RMS augmentait Dans notre e de :
rale (IC 95 % [2,3–4,5] — 3 fois plus pour l’incisive late p < 0,001) ; — 1,64 fois plus dans les cas avec extractions (IC 95 % [1,16–2,33] p < 0,05) ; — 2 fois plus dans les cas de supraclusie (IC 95 % [1,33– 3,53] p < 0,05) ;

55

Rajae ELHADDAOUI et al.

Table IV

Tableau IV

Incidence of MSR according to sex, type of teeth, type of treatment, type of malocclusion, vertical diagnosis, presence of dysfunctions, presence of impacted canines and root morphology.

Incidence des RMS selon le sexe, le type de dents, le type de traitement, le type de malocclusion, le diagnostic vertical, la
sence de dysfonctions, de canine incluse et la morphologie pre radiculaire.

Variables / Variables

Incidence at 18 months (%) /

Incidence at 24 months (%) /

Incidence at 36 months (%) /

Incidence a` 18 mois (%)

Incidence a` 24 mois (%)

Incidence a` 36 mois (%)

Sex / Sexe Male / Masculin
Female / Feminin

15 8.4

37.7 29

75.2 67.4

Type of teeth / Type de dents Central / Centrale
Lateral / Laterale

2.6 6

16.5 46

56.2 82

Type of treatment / Type de traitement Non-extraction / Sans extractions Extraction / Avec extractions

4 2

24 38

54 80

Type of malocclusion / Type de malocclusions Class I ALD / Classe I DDM Class II / Classe II Class III / Classe III

2.8 5.8 18.7

28 34.8 32

67.6 78 50

Vertical diagnosis / Diagnostic vertical Normal / Normal Overbite / Supraclusie
Open bite / Beance

6 3 16

14 35 49

44 76 80

Dysfunctions / Dysfonctions No / Non
Dysfunctional swallowing / Deglutition dysfonctionnelle

9 2.5

22.4 40

61.2 77.4

Impacted canine / Canine incluse No / Non Yes / Oui

3 5

34.4 12.5

71.6 55

Root morphology / Morphologie radiculaire Normal / Normale Root malformation / Dysmorphie radiculaire

0.6 4.5

22.3 40.5

68.6 71.6

56

International Orthodontics 2016 ; 14 : 48-64

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors


sorption des incisives maxillaires apre s traitement orthodontique – e
tude clinique des facteurs de risque La re

Table V

Tableau V


s a` la survenue de RMS en analyse Les facteurs associe
e et multivarie
e. univarie

The factors associated with the occurrence of MSR in univariate and multivariate analysis.

Independent variables /


Variables independantes

Age / Aˆge

Univariate analysis /

Multivariate analysis /


Analyse univariee

HR /

CI 95% /

HR

IC 95 %

1

0.97–1.04


Analyse multivariee

P/p

HR /

CI 95% /

HR

IC 95 %

P/p

0.76

Sex / Sexe Male / Masculin

1


Female / Feminin

0.76

1 0.56–1.03

0.08

0.8

0.56–1.13

0.2

Type of teeth / Type de dents Central / Centrale

1


Lateral / Laterale

2.7

2.00–3.65

< 0.001

1

0.97–1

0.35

1.79–1.32

< 0.001


de traitement Duration of treatment / Duree

1 3.2

2.3–4.5

< 0.001

Type of treatment / Type de traitement Non-extraction / Sans extractions

1

Extraction / Avec extractions

1.8

1 1.64

1.16–2.33

0.005

Type of malocclusion / Type de malocclusion Class I ALD / Classe I DDM

1

1

Class II / Classe II

1.33

0.97–1.84

0.07

1.13

0.8–1.6

0.4

Class III / Classe III

0.7

0.33–1.42

0.31

0.6

0.28–1.35

0.2

Vertical diagnosis / Diagnostic vertical Normal / Normal

1

1

Overbite / Supraclusie

2

1.32–2.86

< 0.001

2.17

1.33–3.53

0.002


Open bite / Beance

2.77

1.80–4.26

< 0.001

3.12

1.66–5.86

< 0.001

0.72–1.64

0.67

0.2–1.4

0.72

1.09–2.07

0.01

Dysfunctions / Dysfonctions No / Non

1

Dysfunctional swallowing /

1.56


Deglutition dysfonctionnelle

1 1.16–2.08

0.04

1.09

Impacted canine / Canine incluse No / Non

1

Yes / Oui

0.63

1 0.4–1.02

0.061

0.53

Root morphology / Morphologie radiculaire Normal / Normale

1

Root malformation / Dysmorphie radiculaire

1.32

1 1.00–1.76

0.04

1.5


HR: high of the resorption / hauteur de la resorption.

International Orthodontics 2016 ; 14 : 48-64

57

Rajae ELHADDAOUI et al.

Table VI Recap of the factors associated in statistically significant manner with the risk of onset of MSR.

Variables / Variables
Lateral incisor / L’incisive laterale Extraction treatments / Les traitements avec extractions Overbite / La supraclusie
Open bite / La beance Root anomalies / Les anomalies radiculaires

Tableau VI


capitulatif des facteurs associe
s de fa¸con statistiquement Re significative au risque de survenue des RMS.

HR / HR 3.2 1.64 2.17 3.12 1.5

CI 95% / IC 95 % 2.3–4.5 1.16–2.33 1.33–3.53 1.66–5.86 1.09–2.07

P/p < 0.001 0.005 0.002 < 0.001 0.01


HR: high of the resorption / hauteur de la resorption.

— 3 for cases of open bite (95% CI [1.66–5.86] P < 0.001); — 1.5 for cases with root abnormalities (95% CI [1.09–2.07] P < 0.05).


ance (IC 95 % [1,66–5,86] — 3 fois plus dans les cas de be p < 0,001) ; — 1,5 fois plus dans les cas avec anomalies radiculaires (IC 95 % [1,09–2,07] p < 0,05).

Discussion

Discussion

Since this was a retrospective study, the evaluation of EARRs and their evolution was performed using the panorex that was part of the standard radiological examination at start and end of treatment and that is also often prescribed during treatment. Unlike a periapical X-ray, the panorex does not enable root length to be measured in millimeters. We therefore chose to use the scores of the Levander and Malmgren classification (1998) [14]. In a previous study [15], the same method was used. The results in terms of prevalence and severity were similar to those of other studies [10,16] that used periapical Xrays.


tude re
trospective, l’e
valuation des Puisqu’il s’agit d’une e
volution a e
te
re
alise
e en utilisant le cliche
RRAE et leur e panoramique qui fait partie du bilan radiologique standard
but et de fin de traitement, et qui est souvent prescrit du de en cours de traitement. La radiographie panoramique ne pertres de la longueur radimet pas une mensuration en millime
ri-apicale, pour culaire comparativement a` la radiographie pe
pour des scores de la classification de cela, nous avons opte
tude Levander et Malmgren (1998) [14]. Dans une e
ce
dente [15], la me ^me me
thode a e
te
utilise
e ; les re
sultats pre
valence et de se
ve
rite
e
taient similaires en termes de pre
tudes [10,16] ayant utilise
la radiographie pe
ria` d’autres e apicale.
tude a concerne
les incisives maxillaires conside
re
es Notre e
tant les dents les plus sujettes aux RRAE : Hollender comme e
une fre
quence des RRAE de 72,9 % au et al. [17] ont rapporte
tait que de niveau des incisives maxillaires, alors qu’elle n’e 34,7 % au niveau des autres dents.
quence des RRAE dans notre e
chantillon e
tait de 95 % La fre
taient des re
sorptions se
ve res. Les donne
es de la dont 19 % e
rature confirmaient ce constat en rapportant une litte
quence des RRAE au niveau des incisives maxillaires de fre
taient des re
sorptions se
ve res 73 % a` 98 %, dont 2 a` 17,2 % e [13,18,19].
notre e
tude sur les re
sorptions Nous avons concentre
re
es a` se
ve res (59,5 % des RRAE dans notre mode
chantillon) ; en termes d’incidence, 10 % de ces RMS survee naient a` 18 mois, 31 % a` 24 mois, alors que 70 % des RMS
tudes pre
ce
dentes survenaient a` partir de 36 mois. D’autres e
taient en accord avec ce constat, en estimant que [10,16,20] e
ve
rite
des re
sorptions augmentait apre s 18 mois de traila se
leve
des RMS ayant e
te
enregistre
tement, le risque le plus e s 33 a` 38 mois de traitement. apre

Our study concerned the upper incisors, which are considered to be the teeth most susceptible to EARR. Hollender et al. [17] noted a frequency of EARR of 72.9% for the maxillary incisors against 34.7% for the other teeth. The frequency of EARR in our sample was 95%, including 19% severe resorptions. Data in the literature confirm this observation, with frequencies of EARR at the level of the upper incisors ranging from 73% to 98%, of which 2 to 17.2% were severe resorptions [13,18,19]. We focused our study on moderate to severe resorptions (59.5% of the EARR in our sample). In terms of incidence, 10% of the cases of MSR occurred at 18 months, 31% at 24 months, and 70% from 36 months onwards. Other studies [10,16,20] confirmed this observation, considering that the severity of resorptions increased after 18 months of treatment; the highest risk for MSR was recorded after 33 to 38 months of treatment.

58

International Orthodontics 2016 ; 14 : 48-64

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors


sorption des incisives maxillaires apre s traitement orthodontique – e
tude clinique des facteurs de risque La re

Several preceding studies [7,9,10,12,16,21–28] looked at the severity of EARR after orthodontic treatment and the factors associated with it: the results of these studies and our study are presented in Table VII.


tudes pre
ce
dentes [7,9,10,12,16,21–28] ont e
tudie
Plusieurs e
ve
rite
des RRAE apre s traitement orthodontique et les la se
s ; la comparaison des re
sultats de facteurs qui y sont associe
tudes avec ceux de la pre
sente e
tude a e
te
pre
sente
e ces e dans le Tableau VII.

Sex and age

^ge Sexe et a

Our study showed that the incidence of MSR was higher in males (75.2% at 36 months) than in females (67.4% at 36 months), although this difference was not statistically significant. As in most previous studies [7,10,12,14,16,25–28], gender does not seem to be a risk factor for MSR.


tude a montre
que l’incidence des RMS e
tait plus Notre e
leve
e chez les hommes (75.2 % a` 36 mois) que chez les e
rence ne fuˆt femmes (67,4 % a` 36 mois), bien que cette diffe pas statistiquement significative. Comme dans la plupart des
tudes pre
ce
dentes [7,10,12,14,16,25–28], le sexe ne seme ^tre un facteur de risque des RMS. blerait pas e ^me que la majorite
des e
tudes ante
rieures De me ^ge n’e
tait pas associe
au risque de [12,14,21,25,27,28], l’a
survenue des RMS (p > 0,05). Mavragani et al. [6] ont montre ^ge chronologique ne serait pas un facteur associe
a` la que l’a
ve
rite
des re
sorptions, mais pluto ^t le degre
de maturite
de se
rentes l’apex, ce qui expliquerait que des sujets de diffe ^ge mais avec le me ^me degre
de maturite
de tranches d’a ^me quantite
de re
sorption l’apex, pourraient avoir la me radiculaire.

In line with majority of previous studies [12,14,21,25,27,28], our results showed no association between age and the risk of occurrence of MSR (P > 0.05). Mavragani et al. [6] showed that it was not chronological age that was a factor associated with the severity of resorption but rather the degree of maturity of the apex, which would explain why subjects in different age groups but with the same degree of apex maturity can present the same level of root resorption.

Tooth type

Le type de dent

As in some other studies [9,10], the lateral incisor was more affected by MSR than the central (HR = 3.2 95% CI [2.3–4.5] P < 0.001). This can be explained essentially by the higher and statistically significant incidence (P < 0.001) of root abnormalities in the lateral incisor compared with the central incisor (Table II). In this study, as in all previous studies [9,10,14,24,26,27], there was a higher incidence of severe resorptions in cases with root abnormalities.

` l’instar des autres e
tudes [9,10], l’incisive late
rale e
tait plus A
e par les RMS que l’incisive centrale (HR = 3,2 IC 95 % touche
par [2,3–4,5] p < 0,001). Ceci serait principalement explique
dominance e
leve
e et statistiquement significative la pre (p < 0,001) d’anomalies radiculaires au niveau de l’incisive
rale comparativement a` l’incisive centrale (Tableau II) ; late
sente e
tude, toutes les e
tudes pre
ce
dentes or, comme la pre
une incidence plus e
leve
e [9,10,14,24,26,27] avaient montre
sorptions se
ve res dans les cas d’anomalies radiculaires. de re

Extractions

Les extractions

It was noted that cases with extractions of the premolars presented higher levels of MSR than cases without extractions (HR = 1.64 95% CI [1.16–2.33] P < 0.05). These results confirm those of previous studies [24–26,28,29] and could be due to the fact that treatments with extractions are generally associated with longer treatment duration and greater amplitude of tooth movement [28,30]. Several preceding studies [14,21,22,24–26,28] showed that the severity of resorption increased with the duration of treatment, although in our study the association between these two factors was not statistically significant (P > 0.05).


que les cas avec extractions de pre
molaires On a constate
sentaient plus de RMS que les cas sans extractions pre
sultats con(HR = 1,64 IC 95 % [1,16–2,33] p < 0,05). Ces re
tudes pre
ce
dentes [24–26,28,29] et ceci firmaient ceux des e ^tre duˆ au fait que les traitements avec extractions pourrait e
ne
ralement associe
s a` des dure
es de traitement et des sont ge amplitudes de mouvements plus importantes [28,30].
tudes pre
ce
dentes [14,21,22,24–26,28] ont monPlusieurs e
que la se
ve
rite
des re
sorptions augmentait avec la dure
e tre de traitement, bien que ces deux facteurs ne fussent pas
s de fa¸con statistiquement significative dans notre associe
tude (p > 0,05). e

Root morphology

La morphologie radiculaire

The results of our study show that the risk of occurrence of MSR was greater in cases with root abnormalities (HR = 1.5


sultats de notre e
tude ont montre
que le risque de Les re
tait plus important dans les cas survenue des RMS e

International Orthodontics 2016 ; 14 : 48-64

59

60

Tableau VII

Comparison of factors associated with severity of resorption of maxillary incisors between previous studies and present study.

Authors / Auteurs

Linge and Linge (1991) /

Sex / Sexe

Age / Aˆge

Duration of treatment /


s a` la se
ve
rite
des re
sorptions des incisives maxillaires Comparaison des facteurs associe
tudes pre
ce
dentes et la pre
sente e
tude. entre les e

Extraction/


de Duree traitement

non-extraction / Extractions/ Non-extractions

Type of malocclusion /

Supraocclusion /

Open bite /

Supraclusion


Beance

Dysfunctional swallowing /

Root morphology / Morphologie radiculaire


Deglutition dysfonctionnelle

Type de malocclusion

No / Non

No / Non

–

–

–

No / Non

Yes / Oui

Yes / Oui

–

–

–

No / Non

–

No / Non

No / Non

Yes / Oui

–

Yes: short roots /

Male ++ /

No / Non

Yes / Oui

No / Non

No / Non

No / Non

–

–

– Yes: blunt apex /

Linge et Linge (1991)

Mirabelle and Artun (1995) / Mirabelle et Artun (1995)

Baumrind et al. (1996)

Oui : racines courtes Masculin ++

Levander et al. (1998)

No / Non

No / Non

Yes / Oui

–

–

–

–

–

Mavragani et al. (2000) Sameshima and Sinclair (2003) /

No / Non No / Non

Yes / Oui Adult > young /

No / Non –

– –

– –

No / Non No / Non

– –

No / Non –

No / Non Yes: pointed/angled apices /

Cl. II,1 > Cl. I /

–

–

–

–

Oui : apex mousses


Oui : apex pointus/coudes

Adulte > jeune

Sameshima et Sinclair (2003)

Brin et al. (2003)

–

–

Yes / Oui

–

Nishioka et al. (2005)

–

–

–

No / Non

–

–

–

No / Non

Yes: root anomaly /

Mohandesan et al. (2007)

Women ++ /

–

Yes / Oui

Yes / Oui

–

–

–

–

–

Adult > young /

Yes / Oui Yes / Oui

Yes / Oui Yes / Oui

– No / Non

– No / Non

– –

– No / Non

– Yes: pointed/angled apices /

Cl. II,1 > Cl. I Oui : anomalie radiculaire

International Orthodontics 2016 ; 14 : 48-64

Femmes ++

Ruo-ping Jiang et al. (2010) Nanekrungsan et al. (2012)

No / Non No / Non

Motakawa et al. (2013)

No / Non

No / Non

No / Non

No / Non

No / Non

–

–

–

Yes: root anomaly /

Lond D Tieu et al. (2014) Present study (2015) /

No / Non No / Non

No / Non No / Non

Yes / Oui No / Non

Yes / Oui Yes / Oui

– No / Non

– Yes / Oui

– Yes / Oui

– No / Non

– Yes: root anomaly /


Oui : apex pointus/coudes

Adulte > jeune

Oui : anomalie radiculaire



Presente etude (2015)

Oui : anomalie radiculaire

Rajae ELHADDAOUI et al.

Table VII

Resorption of maxillary incisors after orthodontic treatment – clinical study of risk factors


sorption des incisives maxillaires apre s traitement orthodontique – e
tude clinique des facteurs de risque La re

95% CI [1.09–2.07] P < 0.05). Other authors have made the same observation [9,10,14,24,26,27], and have shown that the risk was greatest for apical hooks and thin roots [10,26].

d’anomalies radiculaires (HR = 1,5 IC 95 % [1,09–2,07]
tudes ont rapporte
le me ^me constat p < 0,05). D’autres e
que ce risque e
tait plus [9,10,14,24,26,27], et ont montre
es et gre ^ les [10,26]. important dans les cas de racines coude

Open bite


ance Les cas de be

The results of our study also showed that MSR was more frequent in cases with anterior open bite than in cases with normal overbite (HR = 3.12 95% CI [1.66–5.86] P < 0.001). This result is in agreement with that of previous studies [9,12,31,32] and could be explained by the dysfunctional origin of the open bite, accompanied by reciprocating movements [9,31]. In addition, Tanaka et al. [33] and Sringkarnboriboon et al. [34] have shown that the reduction in occlusal function in cases of open bite is a prelude to atrophy of the periodontal ligament which becomes hypofunctional, with weak resistance to external stimuli and thus increased susceptibility to resorption.


sultats de notre e
tude ont e
galement montre
que les cas Les re
ance ante
rieure pre
sentaient plus de RMS que les cas de be de recouvrement normal (HR = 3,12 IC 95 % [1,66–5,86]
sultat e
tait en accord avec celui des e
tudes p < 0,001). Ce re
ce
dentes [9,12,31,32] et pourrait e ^tre explique
par l’origine pre
ance qui s’accompagne de mouvedysfonctionnelle de la be ments de va-et-vient [9,31]. D’autre part, Tanaka et al. [33]
que la ainsi que Sringkarnboriboon et al. [34] ont montre
duction de la fonction occlusale dans les cas de be
ance, re
ludait a` l’atrophie du ligament parodontal qui devient hypopre
sistance aux stimuli externes, fonctionnel, avec une faible re
aux re
sorptions. augmentant ainsi sa susceptibilite

Incisal supraocclusion

Les cas de supraclusion incisive

Unlike most other studies [7,9,10,12,21,26] that evaluated supraocclusion, and that reported no statistically significant association between this factor and the severity of resorption at the level of the upper incisors, our study showed that there were more MSRs in cases with deep bite than in cases with normal overbite (HR = 2.17 95% CI [1.33–3.53] P < 0.05). This result could be explained by the use of intrusive forces which, according to Han et al. [35], increase the surface area of the zone of resorption at the apex by a factor of 4, thereby increasing the severity of the resorption. Similarly, Martins et al. [36] showed that the risk of severe resorptions was greater if intrusive mechanics was associated with retraction of the incisors.


tudes [7,9,10,12,21,26] qui Contrairement a` la plupart des e
value
la supraclusie, et qui n’ont pas rapporte
d’associaont e
ve
rite
tion statistiquement significative entre ce facteur et la se
sorptions au niveau des incisives maxillaires, notre des re
tude a montre
que plus de RMS survenaient dans les cas e
sentant un recouvrement exage
re
que dans les cas de pre recouvrement normal (HR = 2,17 IC 95 % [1,33–3,53]
sultat pourrait e ^tre explique
par l’utilisation p < 0,05). Ce re s Han et al. [35], augmenterde forces d’ingression, qui d’apre
sorbe
e au niveau de aient 4 fois plus la superficie de la zone re
ve
rite
des re
sorptions. De me ^me, l’apex, aggravant ainsi la se
que le risque de survenue de Martins et al. [36] ont montre
sorptions se
ve res e
tait plus important si une me
canique re
te
associe
e a` la re
traction incisive. d’ingression avait e

Conclusion

Conclusion

The frequency of MSR of the maxillary incisors in our study was 59.5%. MSR affected the lateral incisors more often than the centrals. The risk of occurrence of MSR also increased to a statistically significant degree in cases with extractions, in cases of supraocclusion and open bite, and in the presence of root abnormalities. Age, sex, duration of treatment, type of malocclusion, swallowing problems and impacted canines did not show any statistically significant association with the risk of occurrence of MSR. In the light of the risk factors identified in this study and those reported in the literature, it seems useful to suggest some clinical guidelines for the prevention of the occurrence of MSR at the level of the upper incisors:


quence des RMS des incisives maxillaires dans notre La fre
chantillon e
tait de 59,5 %. L’incisive late
rale pre
sentait plus e de RMS que l’incisive centrale. Le risque de survenue des
galement et de fa¸con statistiquement sigRMS augmentait e nificative dans les cas avec extractions, les cas de supraclusie
ance, et en pre
sence d’anomalies radiculaires. et de be ^ge, le sexe, la dure
e de traitement, le type de malocclusion, L’a
glutition dysfonctionnelle et l’inclusion canine n’e
taient la de
s de fa¸con statistiquement significative au risque pas associe de survenue des RMS.
s dans notre e
tude, ainsi Face aux facteurs de risque identifie
nonce
s dans la litte
rature, il nous a semble
inte
resque ceux e sant de proposer des recommandations cliniques en vue de
venir la survenue de RMS au niveau des incisives pre maxillaires :

International Orthodontics 2016 ; 14 : 48-64

61

Rajae ELHADDAOUI et al.

— if resorption evolves quite rapidly, even after withdrawal of orthodontic forces, it is advisable to perform root canal treatment using calcium hydroxide so as to reduce periapical inflammation [8,14,28].

se a` la recherche d’e
ventuelles mala— approfondir l’anamne
miques (arthrose, diabe te, allergies. . .), de prise dies syste
dicamenteuse (notamment des anti-inflammatoires), des me
ce
dents traumatiques ou familiaux de re
sorption ; ante — informer le patient sur le risque de survenue des RRAE et
claire
avant de commencer le obtenir son consentement e traitement orthodontique ;
aliser un bilan radiologique re
troalve
olaire, long co ^ne de — re
fe
rence, avant le traitement, afin de de
celer d’e
ventuelles pre
sorptions anomalies de la morphologie radiculaire, des re
alablement existantes, une inclusion canine. . . etc ; pre
e
duquer les dysfonctions en ge
ne
ral et la de
glutition dys— re
liminer les parafonctions (onyfonctionnelle en particulier et e chophagie, succion de pouce, dysfonctions labiales, bruxisme. . .) ;
e du traitement ; — limiter la dure
des forces orthodontiques a` l’environne— adapter l’intensite ment neuromusculaire et parodontal du patient ; — avoir recours aux protocoles orthodonticochirurgicaux
cessitant des amplitudes de de
placements dans les cas ne dentaires trop importantes ;
rapeutique a` la physiologie apicale — adapter le protocole the en limitant les mouvements a` risque (ingression, torque, tipping. . .) ;
aliser ^ les
guliers, — re des contro radiologiques re
ne
ralement tous les 6 mois pour les dents ante
rieures. ge ^ les devraient e ^tre plus fre
quents chez les patients Ces contro ayant subi un traumatisme, ainsi que chez les sujets sous
leve
de re
sorptions traitement anti-inflammatoire ou a` risque e radiculaires ;
sorptions sont de
tecte
es au cours du traitement, — si des re
tiologie doit e ^tre recherche
e et en fonction de leur leur e
ve
rite
, du nombre de dents atteintes et de l’environnement se ^tre re
e
value
s. parodontal, les objectifs du traitement doivent e
^tre arre ^ te
momenEventuellement, le traitement pourrait e
ment, pendant au moins 3 mois, en maintenant des arcs tane passifs ;
sorptions se de
veloppent assez rapidement, me ^me — si les re s arre ^ t des forces, il serait pre
fe
rable de re
aliser un traiteapre
duire l’inflamment canalaire a` l’hydroxyde de calcium pour re
riapex [8,14,28]. mation au niveau du pe

Disclosure of interest


claration de liens d’inte
re ^ts De

The authors declare that they have no competing interest.


clarent ne pas avoir de liens d’inte
re ^ ts. Les auteurs de

— make a full study of the patient’s medical history, looking for possible systemic diseases (osteoarthritis, diabetes, allergies, etc.), use of medication, in particular anti-inflammatory drugs, traumatic antecedents or family history of resorption; — inform the patient of the risk of occurrence of EARRs and obtain enlightened consent before beginning orthodontic treatment; — perform a full periapical radiological work-up before the treatment, preferably with a long-cone system, so as to detect any abnormal root morphologies, pre-existing signs of resorption, impacted canines, etc; — correct dysfunctions in general and swallowing problems in particular, and eliminate parafunctional activity (nail-biting, thumb-sucking, labial dysfunction, bruxism, etc.); — keep treatment duration short; — adapt the intensity of orthodontic forces to the patient’s neuro-muscular and periodontal environment; — make use of orthodontic-surgical protocols in cases requiring excessively large tooth movements; — adapt the therapeutic protocol to root physiology by limiting movements associated with risk (intrusion, torque, tipping, etc.); — perform regular X-ray checks, generally every 6 months for the anterior segment. These checks should be more frequent for patients who have suffered trauma and for those taking anti-inflammatory treatment or who present a high risk of root resorption; — if resorption is detected during treatment, its etiology should be determined, and depending on its severity, the number of teeth concerned and the periodontal environment, the treatment goals may have to be reviewed. It may be possible to suspend treatment momentarily, for at least 3 months, leaving passive arch-wires in place;

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