ORTHO 282 1-19 Ó 2018 CEO Published by / E´dite´ par Elsevier Masson SAS All rights reserved / Tous droits re´serve´s
Original Article Article original
Is systematic mandibular retention mandatory? A systematic review matiquement une Faut-il prescrire syste matique contention mandibulaire ? Revue syste Hajar Ben Mohimd*, Loubna Bahije, Fatima Zaoui, Abdelali Halimi, Hicham Benyahia Department of Dentofacial Orthopaedics, Consultation and Dental Care Center, Faculty of Dental Medicine, Rabat University of Mohammed V, Allal El Fassi Avenue, Mohammed Jazouli Street, Al Irfane, BP 6212, Rabat Institute, Rabat, Morocco Available online: XXX / Disponible en ligne : XXX
Summary
sume Re
Introduction: Relapse in orthodontics, and particularly, mandibular anterior crowding is an unforeseeable phenomenon and a quite embarrassing situation for the orthodontist, as it may be interpreted by the patient as a treatment failure. Relapse may be inherent to various factors (periodontal, anatomical, muscular, occlusal, residual growth, third molars development. . .), which must be imperatively acknowledged in order to be managed during orthodontic treatment and therefore ensure an optimal control on the stability of the achieved final outcomes. The aim of this review was to determine, through a systematic analysis based on a Medline PubMed search, the scientific relevant factors involved in the relapse of mandibular anterior crowding.
Introduction : La recidive en orthodontie et plus particuliere ment celle de l’encombrement anterieur mandibulaire est un phenom ene imprevisible et embarrassant pour l’orthodon^ interpret ee par le patient comme un echec tiste, et peut etre ^ inherente de son traitement. La recidive peut etre a` plusieurs facteurs (parodontal, anatomique, musculaire, occlusal, crois sance residuelle, evolution des troisiemes molaires. . .) qu’il faut imperativement connaıˆtre pour pouvoir les integrer, les respecter au cours du traitement orthodontique et donc mieux ^ la stabilite des resultats controler obtenus. L’objectif de ce travail est de determiner, a` travers une etude systematique ee a` partir de la base de donnees pub Med, les facteurs realis influen¸c ant la recidive de l’encombrement anterieur mandibu laire scientifiquement prouves. e Materiels et methodes : Une etude systematique a et ee sur la base d’une recherche electronique realis (entre jan vier 2005 et decembre 2016) de plusieurs bases de donnees. e limitee par l’utilisation de plusieurs motsLa recherche a et specifiques cles en deux langues : l’anglais et le fran¸c ais. Deux investigateurs ont retenu celles qui repondaient aux criteres de selection. erences Resultats et discussion : Sur les 1055 ref bibliogra phiques, seules 19 etudes ont correspondu a` nos criteres e traites par ces etudes d’inclusion. Les facteurs qui ont et sont : le traitement avec ou sans extractions, la croissance residuelle, la divergence faciale, le parodonte, le type
Materials and methods: A systematic research was performed based on an electronic search (between 2005 and December 2016) among various databases. The search was limited to the use of several specific search words expressed in two languages: English and French. Two investigators selected those meeting the exclusion/inclusion criteria. Results and discussion: Out of the 1055 references, only 19 studies met our inclusion criteria. The factors addressed by these studies are: extraction or non-extraction treatment, residual growth, facial divergence, periodontium, type of retainer, incisor morphology and quality of dental occlusion. Divergence in
* Correspondence and reprints / Correspondance et tires a` part : Hajar Ben Mohimd, Department of Dentofacial Orthopaedics, Consultation and Dental Care Center, Faculty of Dental Medicine, University of Mohammed V, Rabat, Allal El Fassi Ave, Mohammed Jazouli Street, Al Irfane - BP 6212 Rabat Institute, Morocco. e-mail address / Adresse e-mail :
[email protected] (Hajar Ben Mohimd)
International Orthodontics 2018 ; X : 1-19 http://dx.doi.org/10.1016/j.ortho.2018.01.013
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Ó 2018 CEO. Published by Elsevier Masson SAS. All rights reserved
d’appareillage, la forme des incisives et la qualite de l’occlusion dentaire. La divergence chez les patientes de sexe feminin, une e associes corticale fine et le traitement par les aligneurs ont et e de recidive a` un taux plus elev de l’encombrement mandibu laire anterieur. Cependant, le faible niveau de preuve des etudes incluses ainsi que la variabilite du protocole entre les etudes rend impossible la determination des facteurs dans la recidive reellement impliques de l’encombrement man dibulaire. Des etudes prospectives de qualite sont necessaires pour produire des resultats objectifs et quantifiables a` l’avenir. Ó 2018 CEO. E´dite´ par Elsevier Masson SAS. Tous droits re´serve´s
Key-words
s Mots-cle
female patients, thin cortical bone and treatment using aligners were associated with a higher rate of mandibular anterior crowding relapse. However, due to the low level of evidence of the included studies, as well as the heterogeneity of protocols between the studies, it was not possible to determine factors truly involved in mandibular crowding relapse. Future reliable prospective studies are required to provide unbiased and quantifiable results.
·· ··
Relapse. Anterior mandibular crowding. Stability. Systematic review.
·· ··
cidive. Re rieur. Encombrement mandibulaire ante . Stabilite matique. Revue syste
Introduction
Introduction
In our everyday practice, we have to face treatment options for different types of malocclusions, using different treatment modalities, the aim being to recover a dental occlusion with respect to the different end treatment criteria, in order to ensure the durability of the achieved outcomes. Maintaining tooth alignment involves placing a retention device, most often fixed in the mandibular arch. The orthodontist ensures the control and follows up during a period of time, which varies depending on patient’s motivation. However, a few patients may come back displaying relapse, particularly in the mandibular crowding situations. This leads us to the questions: is relapse ineluctable? Is a systematic mandibular retention device mandatory? And for how long must it be maintained, controlled or even renewed? These issues raise concerns about the factors responsible for relapse of anterior mandibular incisor crowding over middle or a long-term period and in the presence of which we should systematically provide a bonded retainer and maintain it.
a` diffe rentes Dans notre pratique quotidienne, on est confronte rents moyens the rapeutiques, malocclusions a` traiter par diffe tant de retrouver une occlusion dentaire respectant les le but e rents crite res de fin de traitement cense s assurer la diffe rennite du re sultat. Le maintien de l’alignement dentaire fait pe appel a` la mise en place d’une contention, le plus souvent fixe au niveau de l’arcade mandibulaire. L’orthodontiste assure le ^ le et le suivi pendant une pe riode variable en fonction de contro la motivation du patient. Cependant, le retour de quelques cidive n’est pas rare surtout celle de l’encompatients avec une re brement mandibulaire. Ceci nous engage a` nous demander si la cidive est ine luctable ? Faut-il prescrire syste matiquement une re e faut-il la maincontention mandibulaire ? Et pour quelle dure ^ ler et me ^me la renouveler ? tenir, la contro nent a` nous interroger sur les facCes questions nous ame cidive de l’encombrement incisif teurs responsables de la re rieur a` moyen et a` long terme, et en pre sence desquels il infe matiquement mettre une contention colle e et la faut syste maintenir. cidive a e te de finie comme un retour a` la situation initiale, La re apparition partielle ou totale des de sordres denavec une re taires et occlusaux avant traitement orthodontique [1]. L’encombrement incisif mandibulaire est l’une des malocclucidivantes [2–5]. sions les plus re s dans la re cidive de l’encombrePlusieurs facteurs incrimine te cite s dans la litte rature notamment, ment mandibulaire ont e siduelle, le sexe, le traitement avec ou sans la croissance re mes extractions, l’expansion, le parodonte, les troisie re de l’« evidence based dentistry », molaires. . . [6]. A` la lumie ressera a` mettre en e vidence les facteurs ce travail s’inte ellement implique s dans la re cidive de l’encombrement re rieur. mandibulaire ante
Relapse has been defined as a return to the initial situation, with a partial or total reoccurrence of the existing teeth and occlusal disorders before orthodontic treatment [1]. Mandibular incisor crowding is one of the most relapsing malocclusions [2–5]. Several factors have been reported in the literature, mainly, residual growth, gender, extraction or non-extraction treatment, expansion, periodontium, third molars. . .[6]. Highlighted by “evidence based dentistry”, this review is aimed to identify the factors, which are truly involved in the relapse of anterior mandibular crowding.
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ORTHO 282 1-19
Is systematic mandibular retention mandatory? A systematic review
matiquement une contention mandibulaire ? Revue syste matique Faut-il prescrire syste
Materials and methods
riel et me thodes Mate
Search strategy
gie de recherche Strate
A systematic search was performed based on electronic search of several databases (PubMed, Science direct, Cochrane library) including articles published from January 2005 up to December 2016. The search was limited to the following search terms expressed in English and French: “posttreatment stability or relapse” associated with “mandibular anterior alignment” or “mandibular incisor alignment” or “mandibular dental arch alignment” or “mandibular crowding”.
matique a e te effectue e sur la base d’une Une recherche syste lectronique de plusieurs bases de donne es (Pub recherche e Med, Science direct, Cochrane Library) couvrant les publicacembre 2016. La recherche a e te tions de janvier 2005 a` de e par l’utilisation des mots-cle s suivants en anglais et en limite fran¸cais : « posttreatment stability or relapse » en combinaison avec « mandibular anterior alignment or mandibular incisor alignment or mandibular dental arch alignment or mandibular crowding ».
Selection criteria
res de se lection Crite
Selection of the studies was performed based on well-defined criteria: only randomized trials, prospective and retrospective studies, cohorts, case reports published between 2005 and 2016, either in French or English were selected. Patients have to wear a fixed or removable retainer for at least 6 months before removal, and have to follow up at least 3 years a post retention period.
lection des e tudes a e te re alise e sur la base de crite res La se finis, seuls les essais randomise s, les e tudes prospecbien de trospectives, les cohortes, les cas te moins publie s tives, re te entre 2005 et 2016, en langue fran¸caise ou anglaise ont e lectionne s. Les patients devaient avoir porte une contention se fixe ou amovible pendant un minimum de 6 mois avant la pose et e ^tre suivi pendant au minimum 3 ans apre s la de pose de la contention. de
Data extraction
es Recueil des donne
For each of the screened articles, we read the title and abstract, or even some paragraphs (such as objectives, methodology), in order to determine which articles to select. Two reviewers independently extracted the data. If title or abstract did not provide sufficient information regarding the inclusion criteria, it was then necessary to proceed to a full text reading before including or excluding the article. Studies, which did not meet all the inclusion criteria, were excluded from the review. Any disagreements in terms of study selection were resolved by discussion aiming for consensus between the two reviewers. Following assessment of eligibility, 19 studies were included.
s, nous avons proce de a` la Pour chacun des articles recherche sume ou me ^me de certaines sections lecture du titre et du re thodologie) afin de de terminer les articles (objectifs, me lectionner. Cette analyse a e te effectue e en paralle le par a` se valuateurs inde pendants. Dans le cas ou` l’analyse du deux e sume avait laisse un doute quant a` l’e ligibilite de la titre et du re fe rence bibliographique, il e tait alors ne cessaire de re der a` la lecture comple te du document avant de l’inclure proce tudes ne pre sentant pas tous les crite res ou de l’exclure. Les e te rejete es. Les divergences interjuges de d’inclusion ont e lection des articles ont e te re solues par concertation et se rateurs. Apre s obtention d’un consensus entre les deux ope , nous avons inclus 19 articles. valuation de l’e ligibilite e
Results and discussion
sultats et discussion Re
The initial database search identified a total of 123 literature references on Medline (PubMed), 932 on Science Direct and 2 on the Cochrane library with a total of 1055 references titles (fig. 1). After cross reading, 973 titles were excluded: the double articles and those considered as irrelevant. At the end of this procedure, 90 articles were identified. A last, reading allowed to establish the final selection of the relevant articles in reference to the focused issue, and which met the pre-established eligibility criteria. At the end, 19 articles were finally included for the systematic review (Table I). The data factors investigated by these studies were:
es a permis de L’interrogation initiale des bases de donne fe rences bibliographiques sur trouver initialement 123 re Medline (Pub Med), 932 sur Science Direct et 2 sur fe rences (fig. 1). Cochrane Library avec un total de 1055 re s lecture diagonale, 973 articles ont e te e limine s comporApre ` la fin s non pertinents. A tant les articles en doublons et ceux juge tape, 90 articles ont e te identifie s. Une dernie re lecture de cette e tablir la se lection finale des articles pertinents quant a permis d’e e et qui re pondaient aux crite res d’e ligibilite a` la question pose tablis en amont. A` la fin de cette e tape, 19 articles ont e te inclus e finitivement pour la revue syste matique (Tableau I). Les facde te traite s par ces e tudes sont : teurs qui ont e
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[(Fig._1)TD$IG]
Fig. 1: Flux diagram used for litterature data extraction and analysis. pour le recueil et l’analyse des donne es bibliographiques. Fig. 1 : Diagramme de flux utilise
— extraction or non-extraction treatment; — residual growth; — facial divergence; — periodontium type of retainer; — incisor morphology and occlusion quality at the end of treatment.
— les traitements avec ou sans extractions ; siduelle ; — la croissance re — la divergence faciale ; — le parodonte, le type d’appareillage ; de l’occlusion de — la morphologie des incisives et la qualite fin de traitement.
Treatment with and without extractions
Traitement avec ou sans extractions
Long-term stability of incisor alignment is one of the main goals of the orthodontic treatment. The influence of the decision whether to extract or not on this stability has been discussed by several studies [7–9]. In our systematic review, we found 6 included studies comparing extraction or non-extraction treatments in terms of relapse of mandibular incisor crowding (Table II). Indeed, Zafarmand et al. [10], Francisconi et al. [11], Heiser et al. [12] and Erdinc et al. [13] reported no significant difference between the two protocols; this result was in line with Rossouw et al. [9,14] and A rtun et al. results [15]. However, Freitas et al. [16] as well as Myser et al. [17] reported more mandibular incisor crowding relapse in patients treated with extractions. This may be explained by the fact that the distal movement of the canine towards a wider part of the arch leads to an increase of the intercanine width. And, this expansion has been yet strongly incriminated in the relapse of mandibular arch crowding [14,15,18]. Moreover, the mesial drift of the molars reduces the intermolar width, the increase of which has been associated with a better stability [19]. The results of these 2 studies are consistent with the data reported by Kahl-Niekel et al. [20]. Inversely, the results concluded by Uhde et al. [21] and
a` long terme de l’alignement incisif est un des La stabilite objectifs principaux du traitement orthodontique. L’influence cision d’extraire ou non sur cette stabilite a fait l’objet de la de tudes [7–9] Dans notre revue syste matique, de plusieurs e 6e tudes incluses comparant le traitement nous avons trouve cidive de l’encombreavec et sans extractions en termes de re ment mandibulaire incisif (Tableau II). En effet, Zafarmand et Qamari [10], Francisconi et al. [11], Heiser et al. [12] et Erdinc l’absence de diffe rence significative et al. [13] ont rapporte cidive, re sultat qui entre les deux protocoles en termes de re s’accorde avec celui de Rossouw et al. [9,14] et A rtun et al. [15]. Toutefois, Freitas et al. [16] ainsi que Myser et al. [17] ont plus de re cidive d’encombrements mandibulaires incitrouve s avec extractions. Ceci peut e ^tre sifs chez les patients traite par le fait que le de placement distal de la canine vers explique une zone d’arcade plus large entraıˆne une augmentation de la re a e te largeur intercanine. Or, l’expansion de cette dernie e dans la re cidive d’encombrement a` l’arfortement incrimine sial cade mandibulaire [14,15,18]. De plus, le mouvement me duit la largeur intermolaire, dont l’augmentades molaires re te associe e a` une meilleure stabilite [19]. Les re sultats tion a e tudes concordent avec les donne es rapporte es par de ces 2 e sultats Kahl-Niekel et Fischbach [20]. Contrairement aux re
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Is systematic mandibular retention mandatory? A systematic review
matiquement une contention mandibulaire ? Revue syste matique Faut-il prescrire syste
Table I
Tableau I
List of the studies included in the systematic review.
Reference No. /
erence No de ref
[19]
tudes incluses dans la revue syste matique. Liste des e
Author/country/year / Auteur/pays/annee
Title of the study / Titre de l’etude
Raucci et al. (Italy) 2016 / Raucci et al.
Predictors of postretention stability of mandibular dental arch dimensions in patients treated with a lip bumper during mixed dentition followed by fixed appliances Mandibular incisor re-crowding: is it different in extraction and non-extraction cases? Overjet, overbite and anterior crowding relapses in extraction and non extraction patients, and their correlations Stability of treatment with self-ligating brackets and conventional brackets in adolescents: a long-term follow-up retrospective study Post treatment and physiologic occlusal changes comparison Facial divergence and mandibular crowding in treated subjects Searching for predictors of long-term stability
(Italie) 2016
[10]
Zafarmand et al. (Iran) 2014 / Zafarmand et al. (Iran) 2014
[11]
Francisconi et al. (Brazil) 2014 / Francisconi et al. (Brazil) 2014
[69]
Yu et al. (Chine) 2014 / Yu et al. (Chine) 2014
[16]
Freitas et al. (Brazil) 2013 / Freitas et al.
[49]
Goldberg et al. (USA) 2013 / Goldberg et
(Brazil) 2013
[50] [17] [39]
[40]
al. (Etats-Unis) 2013 Franklin et al. (USA) 2013 / Franklin et al. (E tats-Unis) 2013 Myser et al. (USA) 2012 / Myser et al. (E tats-Unis) 2012 Fudalej (USA) 2010 / Fudalej (Etats-Unis) 2010
Fudalej et al. (Poland) 2010 / Fudalej et al. (Pologne) 2010
[12]
Heiser W (Austria) et al. 2008 / Heiser W et al. (Autriche) 2008
[41]
Fudalej (Poland) 2008 / Fudalej (Pologne) 2008
[42]
Fudalej and Artun (Poland) 2007 / Fudalej
[64]
Kuncio et al. (USA) 2007 / Kuncio et al.
[79]
Freitas et al. (Brazil) 2007 / Freitas et al.
[13]
Erdinc et al. (Turkey) 2006 / Erdinc et al.
and Artun (Pologne) 2007 (E tats-Unis) 2007
(Brazil) 2007 (Turquie) 2006
[28]
Janson et al. (Brazil) 2006 / Janson et al. (Brazil) 2006
[55] [70]
Rothe et al. (USA) 2006 / Rothe et al.
(E tats-Unis) 2006 Freitas et al. (Brazil) 2006 / Freitas et al. (Brazil) 2006
International Orthodontics 2018 ; X : 1-19
Long-term stability: post retention changes of the mandibular anterior teeth Relapse of mandibular incisor alignment is not associated with the total post treatment mandibular rotation Is post adolescent mandibular anterior growth rotation a risk factor for relapse of incisor alignment in males? Association of the canine guidance angle with maxillary and mandibular intercanine widths anterior alignment relapse: extraction vs non extraction treatment Effects of post treatment skeletal maturity measured with the cervical vertebral maturation method on incisor alignment relapse Mandibular growth rotation effects on post retention stability of mandibular incisor alignment Invisalign and traditional orthodontic treatment post retention outcomes compared using the American Board of Orthodontics objective grading system Influence of the quality of the finished occlusion on post retention occlusal relapse Relapse of anterior crowding in patients treated with extractions and non extractions of premolars Alignment stability in class II malocclusion treated with 2- and 4-premolars extractions protocols Trabecular and cortical bone as risk factors for orthodontic relapse Correlation between mandibular incisor crown morphologic index and post retention stability
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Table II
Tableau II
Included studies comparing extraction and non extraction treatments.
Authors / Auteurs Zafarmand et al. [10]
Etudes incluses comparant le traitement avec ou sans extractions.
Sample characteristics / Caracteristiques de
Conclusion / Conclusion
40 patients; extraction group, n = 21, non extraction group, n = 19; Irregularity Index / 40
Treatments with or without extraction are two different protocols but they both show the same tendency for incisor crowding relapse / Les
l’echantillon
patients ; groupe avec extraction, n = 21, groupe sans extraction, n = 19 ; Irregularity Index
Francisconi et al. [11]
Group 1: no extractions, 12.96 years; group 2: extraction of the 4 premolars, 13.01 years; fixed retention 33–43 (1.44 yrs). Postretention period 3.81 years / Groupe 1 : sans extractions, 12,96 ans ; groupe 2 : avec extractions des 4 premolaires, 13,01 ans ; contention fixe 33–43 (1,44 ans). Periode postcontention 3,81 ans
Freitas et al. [16]
269 patients with Cl I–II malocclusion; age 13– 16 years; 3 groups: 1st (n = 97, treatment with extraction), 2nd (n = 58, no extraction), 3rd (n = 114 untreated); fixed mandibular retention 33–43; Irregularity Index, PAR (occlusion) / ^ 269 patients avec malocclusion Cl I–II ; age 13–16 ans ; 3 groupes : 1er(n = 97, Traitement avec extraction), 2e(n = 58, sans extraction), ; contention 3e(n = 114 non traites) mandibulaire fixe 33–43 ; Irregularity Index, PAR (occlusion)
Myser [17]
25 patients; good final occlusion; age at the end of treatment < 21 years; minimum post retention period 3 years / 25 patients ; occlusion de fin de traitement satisfaisante ; ^ de fin de traitement < 21 ans ; periode age postcontention minimum 3 ans
Erdinc [13]
98 patients: class I or II malocclusion, Edgewise mechanics; 2 groups 1st (n = 49 patients treated without extraction, 2nd (n = 49 patients treated with extraction; Hawley’s retainer: 2 years; 4 years, 11 months; Irregularity Index / 98 patients : malocclusion de class I ou II, mecanique Edgewise ; 2 groupes : 1er(n = 49 sans extractions, 2e (n = 49 patients traites avec extractions ; contention de patients traites Hawley : 2 ans ; periode postcontention : 4 ans, 11 mois ; Irregularity Index
6
traitements avec ou sans extractions sont deux protocoles therapeutiques differents, mais qui ^ presentent la meme tendance a` la recidive d’encombrement incisif
Absence of significant difference between extraction and non extraction treatments in terms of relapse and mandibular crowding /
Absence de difference significative entre les traitements avec ou sans extractions en terme de recidive de l’encombrement mandibulaire
Relapse of anterior mandibular crowding was significantly higher in extraction patients compared to untreated patients / La recidive
d’encombrement anterieur mandibulaire etait significativement plus importante chez les avec extractions par rapport aux patients traites sujets non traites
Treatments with extraction lead to more relapse than non extraction treatments; a wide anterior part of the arch is related to long-term stability; interproximal restorations are risk factors for mandibular crowding relapse / Les traitements
avec extractions sont plus recidivants que les traitements sans extractions ; une forme large a` une de la region anterieure de l’arcade est liee stabilite a` long terme ; les restaurations interproximales sont des facteurs de risque de recidive d’encombrement mandibulaire
No significant difference concerning mandibular crowding relapse between premolar extraction and non extraction cases; relapse was minimal in both groups / Aucune difference
significative concernant la recidive d’encombrement mandibulaire entre les cas avec ou sans extractions de traites premolaires ; la recidive etait minime dans les 2 groupes
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Is systematic mandibular retention mandatory? A systematic review
matiquement une contention mandibulaire ? Revue syste matique Faut-il prescrire syste
Table II
Tableau II
Included studies comparing extraction and non extraction treatments. (following)
Authors / Auteurs Heiser [12]
Etudes incluses comparant le traitement avec ou sans extractions. (suite)
Sample characteristics / Caracteristiques de
Conclusion / Conclusion
30 patients treated without extractions, 30 with extractions of the 4 premolars; straight archwire technique; initial crowding 5.4 mm; SAM 2 simulator; removable retention / 30 patients
Absence of significant difference between extraction and non extraction treatments in terms of mandibular crowding relapse /
l’echantillon
sans extractions, 30 avec extraction des traites 4 premolaires ; technique d’arc droit ; encombrement initial 5,4 mm ; articulateur SAM 2 ; contention amovible
Absence de difference significative entre les traitements avec ou sans extraction en terme de recidive d’encombrement mandibulaire
Paquette et al. [22] reported a higher amount of relapse in patients treated without extractions.
conclus par Uhde et al. [21] et Paquette et al. [22] qui ont un taux de re cidive plus important chez les patients rapporte s sans extractions. traite
Treatment of class II malocclusions with extractions
Traitement des malocclusions de classe II avec des extractions
Treatment of class II malocclusions with extractions consists in two different protocols: the monomaxillary extractions and the bimaxillary extractions [23]. The choice between these two protocols mainly depends on the presence or absence of discrepancy in the mandibular arch. Bimaxillary extractions are generally indicated for mandibular crowding [24,25]. But in some cases of severe occlusal class II with slight to moderate mandibular crowding, monomaxillary extractions associated or not with mandibular stripping, may be indicated, in order to facilitate treatment mechanics [26,27]. However, these procedures may potentially influence the long-term stability of mandibular incisor alignment.
Le traitement par extractions des malocclusions de classe II rents protocoles : les extractions monofait appel a` deux diffe maxillaires et les extractions bimaxillaires [23]. Le choix entre pend essentiellement de la pre sence ces deux protocoles de ou pas de dysharmonie dentomaxillaire (DDM) a` l’arcade ne ralement mandibulaire. Les extractions bimaxillaires sont ge es en cas de DDM mandibulaire [24,25]. Mais, dans indique ve re avec un encombrecertains cas de classe II occlusale se re , les extractions monomaximent mandibulaire faible a` mode es ou non a` un stripping mandibulaire peuvent llaires associe ^tre indique es afin de faciliter la me canique du traitement e dures risquent d’influencer la [26,27]. Cependant, ces proce a` long terme de l’alignement incisif mandibulaire. stabilite tude syste matique, une seule e tude [28] a Dans notre e la stabilite a` long terme de l’alignement incisif entre compare s par les extractions les cas de malocclusion de classe II traite s par les extractions monomaxilbimaxillaires et ceux traite rence significative laires (Tableau III). Il n’existe aucune diffe cidive de l’encomentre les deux protocoles en termes de re es concordent avec les brement mandibulaire. Ces donne sultats des e tudes qui ont compare le traitement des malre occlusions de classe II division 1 avec et sans extractions des molaires [9,15,29], contrairement a` Kahl-Nieke et al. qui 4 pre une diffe rence significative entre les traitements ont rapporte chantillon de cette avec et sans extractions [20]. Cependant, l’e tude comportait a` la fois les malocclusions de classe I, II et III. e
In our systematic review, only one study [28] compared the long-term stability of incisor alignment between class II cases treated with bimaxillary extractions and those treated with monomaxillary extractions (Table III). They found no significant difference between the two protocols in terms of mandibular crowding relapse. These findings are in agreement with the results of studies, which compared the treatment of class II division 1 malocclusions with and without extraction of the 4 premolars [9,15,29]. Unlike Kahl-Nieke et al. [20] who reported a significant difference between extraction and non-extraction treatments. However, the sample of this study included class I, II and III malocclusions as well.
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Table III
Tableau III
Included study comparing treatments of Class II malocclusions with monomaxillary vs bimaxillary extractions.
Authors / Auteurs Janson et al. [28]
Etude incluse comparant le traitement des malocclusions de Classe II par extractions monomaxillaires vs bimaxillaires.
Sample characteristics / Caracteristiques de
Conclusion / Conclusion
Group 1: 19 patients, mean age 14.04 years, extraction of 2 maxillary premolars, out of which 10 patients with mandibular stripping / Groupe
No significant difference in incisor alignment stability in class II patients treated with extractions monomaxillary or bimaxillary significative (P < 0.05) / Aucune difference
l’echantillon
^ moyen 14,04 ans, 1 : 19 patients, age extractions de 2 premolaires maxillaires, dont 10 patients avec stripping mandibulaire Group 2: 47 patients, mean age 13.03 years, extraction of the 4 premolars / Groupe 2 : 47 ^ moyen 13,03 ans, extractions de 4 patients, age premolaires Sub-group from group 2 = with extraction of the 4 premolars (initial IIRcomparable to group 1) / Sous-groupe issu du groupe 2 = avec extractions des 4 premolaires (IIR initiale comparable au groupe 1 Edgewise treatment, 2 yrs of fixed mandibular retention, postretention period of 3 years / Traitements Edgewise, contention mandibulaire fixe de 2 ans, periode de postcontention de 3 ans
dans la stabilite de l’alignement incisif chez les avec extractions sujets de classe II traites monomaxillaires ou bimaxillaires (p < 0,05)
Residual growth
siduelle La croissance re
Several patients end their orthodontic treatment when adolescence is almost achieved and craniofacial growth is still ongoing. The role of this residual growth in the relapse of mandibular crowding is still discussed. Indeed, Bj€ork and Skieller have shown that when metal implants are placed in the mandibular arch, an excessive vertical growth occurs in the condyles [30,31], which is responsible for a mean anterior rotation of the mandible of about 6 [32]. This growth might have some impact on the interincisor relationships and on the arch width as well, and therefore influence the anterior tooth alignment [33,34]. Moreover, according to Bj€ork’s findings, the marked anterior rotation is a risk factor for the occurrence of mandibular incisor crowding [35]. This is explained by the tendency of the incisors to follow the mandibular rotation, thus leading to a reduction or a total loss of the interincisor contacting point, and a subsequent decrease of the interincisor angle [36]. Richardson [37] and Perera [38] also concluded in their studies that the anterior rotation of the mandible might contribute to the occurrence of a late incisor crowding.
Plusieurs patients terminent leur traitement orthodontique vers la fin de l’adolescence ou` la croissance craniofaciale sente. Le ro ^ le de cette croissance re siduelle est toujours pre apparition de l’encombrement mandibulaire est toudans la re . En effet, Bjo €rk et Skieller avaient montre gra ^ce jours discute talliques a` l’arcade mandibulaire, un exce s a` des implants me de croissance condylienne verticale [30,31] responsable rieure de la mandibule de 6 en moyenne d’une rotation ante [32]. Cette croissance pourrait avoir un impact sur les rapports interincisifs ainsi que la largeur d’arcade mandibulaire et donc rieur [33,34]. De plus, influencer l’alignement dentaire ante €rk, la rotation ante rieure selon les constatations de Bjo e est un facteur de risque pour l’apparition d’un prononce encombrement mandibulaire incisif [35]. Ceci est explique par la tendance des incisives a` suivre la rotation mandibulaire entraıˆnant une diminution ou une perte totale du point de quence la diminution contact interincisif et avec comme conse de l’angle interincisif [36]. Richardson [37] et Perera [38] ont galement conclu dans leurs e tudes que la rotation ante rieure e de la mandibule pourrait contribuer a` l’apparition de l’encombrement incisif tardif. nombre 4e tudes (Tableau IV) testant Notre recherche a de siduelle apre s la fin du l’implication de la croissance re
Our research identified 4 included studies (Table IV) investigating the implication of residual growth following the end
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Table IV
Tableau IV
Included studies assessing residual growth.
tudiant la croissance re siduelle. Etudes incluses e
Authors / Auteurs
Sample characteristics / Caracteristiques de
Conclusion / Conclusion
Fudalej et al. [39]
2 groups: 1st with II1 6 mm, 2nd stable II 3 mm; minimum postretention period 10 yrs; mandibular rotation: angle between line SN to T2 and T3 / 2 groupes : 1eravec
Mandibular rotation is not associated with anterior mandibular crowding relapse (P 0.05); the skeletal and dental changes related to posttreatment growth are similar in both groups / La rotation mandibulaire n’est
l’echantillon
II1 6 mm, 2estable II 3 mm ; periode postcontention minimun 10 ans ; rotation mandibulaire : angle entre ligne SN a` T2 et T3
Fudalej [40]
2 male groups: 1st with maximum mandibular AR and 2nd with minimum AR / 2 groupes de gar¸c ons : 1eravec maximum de rotation mandibulaire anterieure et 2eavec minimum de rotation mandibulaire anterieure Postretention period: 10 years / Periode postcontention 10 ans
Fudalej [41]
2 groups: 1st with II > 6 mm, 2nd with II < 3.5 mm; age at the end of treatment 18 years; II = measure of crowding; CVM status on lateral cephalogram (C2,C3,C4) / 2 groupes : 1eravec II > 6 mm, 2eavec ^ en fin de II < 3,5 mm ; age traitement 18 ans ; II = mesure d’encombrement ; statut MCV sur eradiographie tel (C2,C3,C4)
Fudalej et al. [42]
3 groups: 1st with SFH 46 patients, 2nd with 42 patients and NFH, 3rd with 35 patients and LFH, similar ages; II; intercanine width; minimum postretention period: 10 yrs / 3 groupes : 1eravec 46 patients HFC, 2eavec 42 patients et HFN, 3eavec 35 patients et HFL, ^ age similaire ; II ; largeur intercanine ; periode postcontention minimum 10 ans
a` la recidive pas associee d’encombrement anterieur mandibulaire (p 0,05) ; les a` changements squelettiques et dentaires lies traitement chez les 2 la croissance apres groupes sont similaires
Postadolescent anterior mandibular rotation is not associated with mandibular crowding relapse; a marked anterior mandibular rotation does not aggravate incisor crowding relapse /
La rotation anterieure mandibulaire post a` la recidive adolescente n’est pas associee d’encombrement mandibulaire ; la rotation n’aggrave mandibulaire anterieure prononcee pas la recidive de l’encombrement incisif
Skeletal maturity assessed at the end of orhtodontic treatment through CVM is not associated with mandibular crowding relapse; the Irregularity Index before treatment and during the non retention period were correlated with the increase of crowding a` ee relapse / La maturite squelettique evalu la fin du traitement orthodontique par MCV a` la recidive n’est pas associee de l’encombrement mandibulaire ; l’Index d’Irregularit e avant traitement et periode sans e a` l’augmentation de contention etaient correl la recidive d’encombrement
The long or short facial pattern at the end of orthodontic treatment traitement was not associated with a high risk of mandibular crowding relapse in adolescent patients; anterior growth was significantly more frequent in males, with may explain their high facial long ou court relapse rates / Le schema a` la fin du traitement orthodontique n’est pas e de recidive associe a` un risque elev d’encombrement mandibulaire chez les patients adolescents ; la croissance anterieure etait significativement plus frequente chez les gar¸c ons, ce qui peut e de recidive expliquer leurs taux elev
II: Irregularity Index; AR: anterior rotation; CVM: cervical vertebral maturation; SFH: short facial height; NFH: normal facial height; LFH: long facial height. II : Index d’Irregularit e ; RA : rotation anterieure ; MCV : maturation cervicovertebrale ; HFC : hauteur faciale courte ; HFN : hauteur faciale normale ; HFL : hauteur faciale longue.
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However, the same studies [39,40,42] questioned the reliability of these results by mentioning the several features, which may affect the observed changes. Indeed, when the centre of rotation of the mandible is located on the incisal edge, the posterior facial height increases without affecting the overjet and the overbite. In this case, the incisor alignment is maintained, inversely to a situation located far from the incisor edge and close to the temporomandibular joint where changes in the incisor region are expected [4,35]. Moreover, assessment of the amount of mandibular rotation through the SN/Go-Gn angle is performed by superimposition on the internal structures of the symphysis and the mandibular canal as references. Now, the basilar edge of the mandibular corpus is prone to remodelling processes, which could mask the real amount of mandibular rotation [31,32,42].
cidive de l’encombrement traitement orthodontique dans la re rieur [39–42]. Aucune de ces e tudes n’a pu associer la ante siduelle a` la re apparition ou a` l’aggravation de croissance re sultat est en accord avec les l’encombrement incisif. Ce re es rapporte es par Sinclar et Little ainsi que Williams et donne Andersen [43–45]. ^mes e tudes [39,40,42] mettent en cause la Cependant, ces me sultats en e voquant plusieurs e le ments certitude de ces re s. En effet, lorsque pouvant affecter les changements observe sur le bord incisif, la le centre de rotation mandibulaire est situe rieure augmente sans affecter les surhauteur faciale poste plombs horizontal et vertical. L’alignement incisif est dans ce loigne e du bord cas maintenu contrairement a` une situation e nisque temporomandibulaire ou` les incisif et proche du me gion incisive sont attendus [4,35]. changements dans la re valuation de la quantite de rotation mandibulaire De plus, l’e a` travers l’angle SN/Go-Gn se fait par superposition, avec fe rence les structures internes de la symphyse et comme re le canal mandibulaire. Or, le bord basilaire du corps mandibunome nes de remodelage qui pourraient laire est sujet aux phe de rotation mandibulaire [31,32,42]. masquer la vraie quantite
Facial divergence
La divergence faciale
Incisor crowding has been associated with vertical growth and increase in the vertical dentoalveolar eruption [33,46,47]. The latter also increases with divergence. This may suggest some association between crowding and facial divergence related to the decrease of the arch perimeter subsequent to the coronolingual tipping of the incisors [32,48].
te associe a` la croissance verticale L’encombrement incisif a e ruption dentoalve olaire verticale et a` l’augmentation de l’e re augmente e galement avec la diver[33,46,47]. Cette dernie rer une association entre l’encombregence. Ceci peut sugge ment et la divergence faciale en rapport avec la diminution du rime tre d’arcade a` la suite de la version coronolinguale des pe incisives [32,48]. matique, une seule e tude incluse [49] Dans notre revue syste resse e au rapport de la divergence faciale avec la s’est inte cidive de l’encombrement incisif ; l’association entre ces re le ments a e te rapporte e uniquement chez les patientes deux e minin (Tableau V). Cette diffe rence entre les sexes de sexe fe ^tre attribuable au fait que les patientes de sexe pourrait e minin e taient plus divergentes. Une autre e tude incluse a fe comme facteurs pre dictifs de l’instabilite de l’alignement rapporte gression. incisif, le sens vertical et ceci a` travers l’analyse de re que pour chaque degre En effet, les auteurs ont trouve sultait une augd’augmentation de l’angle SNa/Go-Gn a` T1, il re gularite incisive de 0,11 mm de T2–T3 [50]. mentation de l’irre galement rapporte Nasbi et al. [51] et Sakuda et al. [52] ont e cidive de une association entre la divergence faciale et la re rences signifil’encombrement mandibulaire, mais sans diffe tudes catives entre les deux sexes. Cependant, d’autres e aucune association entre la divergence et n’ont trouve de l’alignement incisif [53,54]. l’instabilite
of orthodontic treatment in the relapse of anterior crowding [39–42]. None of these studies were able to associate residual growth with reoccurrence or aggravation of anterior incisor crowding. This finding is consistent with the data reported by Sinclair and Little and Williams and Andersen [43–45].
In our systematic review, only one included study [49] focused on the ratio between facial divergence and relapse of incisor crowding; the association between these two elements was reported only in female patients (Table V). This difference within genders might be due to the fact that female patients were more divergent. Another included study reported the vertical dimension as a predictive factor of incisor alignment instability, using regression analysis. Indeed, the authors found that for each degree of SN/Go-Gn angle increase at T1, resulted an increase of the incisor irregularity of 0.11 mm from T2 to T3 [50]. Nasbi et al. [51] and Sakuda et al. [52] have also reported an association between facial divergence and relapse of mandibular crowding, but with no significant differences between the two genders. However, other studies have found no association between divergence and incisor alignment instability [53,54].
Periodontium
Le parodonte
Teeth are anchored and moved within the alveolar bone. This movement may be affected by bone density. Only one included study reported on the influence of bone on the relapse rate in mandibular crowding by assessing bone structure and
es et de place es au sein de l’os alve olaire. Les dents sont ancre placement peut e ^tre affecte par la densite osseuse. Une Ce de tude incluse a porte sur l’influence de l’os sur le taux de seule e cidive de l’encombrement mandibulaire en e valuant la re
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Table V
Tableau V
Etude traitant la divergence faciale.
Study investigating facial divergence.
Authors / Auteurs
Sample characteristics / Caracteristiques
Conclusion / Conclusion
Goldberg et al. [49]
75 patients (31 males, 44 females) treated with extractions of the 4 premolars and Edgewise mechanics; minimum post retention period of 5 years; cephalometric measurements (HFA, HFP, IMPA, MPA. . .); measurements on casts (IC, IM, II, TSALD widths) / 75 patients (31
Crowding relapse was generally minimal /
de l’echantillon
avec hommes, 44 femmes) traites extraction des 4 premolaires et mecanique Edgewise ; periode postcontention minimum de 5 ans ; mesures cephalometriques (HFA, HFP, IMPA, MPA. . .) ; mesures sur moulage (largeurs IC, IM, II, TSALD)
La recidive d’encombrement etait eralement gen minime Female patients with the most increased facial divergence showed momultibracket / Les patientes femmes avec la divergence presentaient faciale la plus augmentee plus d’encombrement Female patients with the highest lower incisor eruption incisive inferior and the most facial divergence after end of treatment showed significantly momultibracket relapse / Les patientes avec le plus d’eruption incisive inferieure et fin de le plus de divergence faciale apres traitement presentaient significativement plus de recidive d’encombrement
IC: intercanine; IM: intermolar; II: Irregularity Index; TSALD: tooth size-arch length discrepancies: difference between arch length and teeth diameter. des dents. IC : intercanine ; IM : intermolaire ; II : Index d’Irregularit e ; TSALD : difference entre la longueur d’arcade et le diametre
thickness on radiographs, using two parameters: the mandibular cortical bone thickness and the alveolar bone structure, searching for any correlation (Table VI). This study reported more relapse in patients with thin cortical bone [55]. Now, it has been demonstrated that the thickness of the cortical bone reflects the overall bone support [56]. Therefore, we can presume that relapse is more frequent in patients with a reduced skeletal support. This result suggests the possible role of mandibular bone in the multifactorial relapse of incisor crowding. Indeed, a thin cortical bone involves a poor bone density, and thus less bone support to maintain teeth alignment.
paisseur de l’os sur radiographie a` travers deux structure et l’e tres : l’e paisseur corticale mandibulaire et la structure parame olaire, a` la recherche d’une e ventuelle corre lation alve tude a rapporte plus de re cidive chez (Tableau VI). Cette e te de montre les sujets avec des corticales minces [55]. Or, il a e paisseur de la corticale refle te la densite osseuse gloque l’e cidives sont plus bale [56]. Donc, on peut supposer que les re quentes chez les patients avec un faible support osseux. fre sultat sugge re le ro ^ le possible de l’os mandibulaire dans Ce re cidive multifactorielle de l’encombrement incisif. En effet, la re paisseur corticale implique une faible densite une faible e osseuse et donc moins de soutien osseux pour maintenir l’alignement dentaire.
Type of device or applied technique
e Le type d’appareillage ou la technique utilise
In our systematic review, we found 3 included studies investigating the impact of treatment modality on the long-term stability of incisor alignment (Table VII).
matique, nous avons trouve 3e tudes Dans notre revue syste valuant chacune l’impact d’une technique de traiteincluses e a` long terme de l’alignement incisif ment sur la stabilite (Tableau VII).
Expansion using a lip bumper
Expansion par le lip bumper
The lip bumper is a device used to reduce teeth crowding [57,58]. By changing the force of the lip and cheek muscles, it allows [59] a significant increase of the intercanine [57,58], premolar [57] and intermolar [60,61] widths and the arch perimeter and length as well [61]. The long-term stability of
pour re duire l’encombreLe lip bumper est un dispositif utilise rant la force des musculatures ment dentaire [57,58]. En alte labiale et jugale, il permet [59] une augmentation significative molaire [57] et interdes largeurs intercanine [57,58], interpre rime tre et de la longueur molaire [60,61] ainsi que du pe
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Table VI
Tableau VI
ressant le parodonte. Etude incluse inte
Included study focusing the periodontium.
Sample characteristics / Caracteristiques de
Conclusion / Conclusion
Group 1: relapse with II 6 mm; group 2: control group, stable with II 3 mm / Groupe 1 : recidive
Subjects with thin cortical bones are significantly more prone to a risk of relapse following orthodontic treatment (P < 0.05) / Les sujets avec des
Authors / Auteurs Rothe et al. [55]
l’echantillon
^ avec II 6 mm ; groupe 2 : groupe de controle, stable avec II 3 mm Minimum postretention period of 10 years; measurements: Incisor Irregularity Index (II), thickness of cortical bone on the panoramic and lateral cephalogram radiographs; assessment of the trabecular components / Periode postcontention minimum 10 ans ; mesures : Index d’Irregularit e incisif (II), epaisseur de la corticale sur panoramique eradiographie et tel ; evaluation des structures trabeculaires
corticales minces ont significativement plus de risque de recidive apres traitement orthodontique (p < 0,05)
Inversely, Ferris et al. [62] reported a higher decrease in the intermolar, interpremolar and intercanine widths of 1.5, 1.2 et 0.9 mm, respectively, and Solomon et al. [63] also reported a significant decrease of 1.2 mm only for the interpremolar width, while the intercanine and intermolar widths decreased of 0.4 and 0.6 mm, respectively. The higher relapse rates reported in these two studies might be related to a greater mechanical expansion during the active multibracket fixed treatment.
a` long terme de ces re sultats est d’arcade [61]. La stabilite e. L’e tude [19] incluse dans notre revue toujours controverse dictifs de la avait comme objectif d’identifier les facteurs pre de l’arcade mandibulaire chez les patients traite s en stabilite denture mixte par un arc transpalatin maxillaire et un lip bumper mandibulaire suivi par un traitement multibague en den que les ture permanente (Tableau VII). Les auteurs ont trouve dicteurs de la stabilite e taient les largeurs intermeilleurs pre molaires mandibulaires apre s une phase molaires et interpre s de stainitiale de traitement par lip bumper. Les probabilite apre s de pose de la contention (moyenne de 4 ans apre s bilite ^ t) ont augmente de 1,52 et 2,7 fois respectivement, son arre tre d’expansion des largeurs intermolaire pour chaque millime molaire au cours du traitement. Ainsi, le taux de et interpre cidive de l’encombrement e tait tre s minime (0,34 mm). re une diminution plus Inversement, Ferris et al. [62] ont rapporte leve e des largeurs intermolaire, interpre molaire et intercae nine de 1,5, 1,2 et 0,9 mm, respectivement et Solomon et al. des diminutions significatives de 1,2 mm pour [63] ont signale molaire seulement, tandis que les largeurs la largeur interpre de 0,4 et 0,6 mm. Les intercanine et intermolaire ont diminue cidive plus e leve dans ces deux e tudes sont peuttaux de re ^tre lie s a` une plus grande expansion me canique durant le e traitement actif multibague.
Treatment with aligners
Traitement par les aligneurs
Treatment with aligners is an alternative to fixed multibracket fixed treatment. They include an aesthetic technique allowing moving and aligning teeth using a series of removable splints.
Le traitement par aligneurs est une alternative aux traitements par appareillages fixes. Ils constituent une technique esthe placement et l’alignement des dents tique permettant le de rie de gouttie res amovibles. a` l’aide d’une se tude incluse dans notre revue [64], l’auteur a rapporte Dans l’e cidive de l’encombrement mandibulaire plus un taux de re
these results is still discussed. The included study [19] in our review was aimed to identify the predictive factors for mandibular arch stability in patients treated in mixed dentition, using a maxillary transpalatal arch and a mandibular lip bumper, followed by a multibracket fixed treatment in permanent dentition (Table VII). The authors found that the best predictors for stability were the mandibular intermolar and interpremolar widths after an initial treatment phase using a lip bumper. The probabilities for stability following retainer removal (mean of 4 years after retention) were increased by 1.52 and 2.7 respectively, for each millimeter of expansion in the intermolar and interpremolar widths during treatment. Hence, the crowding relapse rate was minimal (0.34 mm).
In the study included in our review [64], the author reported a higher rate of mandibular crowding relapse in patients treated
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Table VII
Tableau VII
Included studies on the type of appliance.
Authors / Auteurs
Raucci et al. [19]
Yu et al. [69]
Kuncio et al. [64]
Etudes incluses traitant le type d’appareillage.
Study designs / Schemas de l’etude 31 patients divided into a stable group and a group with relapse; Cl. I or II malocclusions; age 9 yrs to T0; T0 to T1: 2 years of lip bumper en in mixed dentition / 31 patients divises
groupe stable et groupe avec recidive ; ^ 9 ans a` T0 ; malocclusions de Cl. I ou II ; age T0a` T1 : 2 ans de lip bumper en denture mixte T1 to T2: multibracket treatment in permanent dentition; 2 years minimum of fixed retention; post retention period: meanly 4 years / T1a` T2 : traitement multibague en denture permanente ; contention fixe 2 ans minimum ; periode postcontention : 4 ans en moyenne
Group 1: passive self-ligating brackets, mean age 13.56 yrs; group 2: conventional brackets; initial mean age 13.48 yrs / Groupe 1 : ^ moyen brackets autoligaturants passifs, age 13,56 ans ; groupe 2 : brackets ^ moyen initial 13,48 ans conventionnels, age
2 groups: Invisalign vs multibracket treatment; removable retention; postretention period of 3 years / 2 groupes : Invisalign vs multibagues ; contention amovible ; periode postcontention de 3 ans
Conclusions / Conclusions The stability odds ratio during post- retention increases of 1.52 and 2.7 respectively for each 1 mm increase of the intermolar and interpremolar distance intermolaire et interpremolaire using the lip bumper / L’ods de stabilite en postcontention augmente de 1,52 et 2,7 respectivement pour chaque augmentation de 1 mm de la distance intermolaire et interpremolaire par le lip bumper
No significant difference between the selfligating brackets and conventional brackets in terms of stability / Aucune difference significative entre les brackets autoligaturants et les brackets conventionnels en terme de stabilite
Patients treated with aligners showed more relapse compared to those treated with a conventional appliance / Les patients traites avec les aligneurs presentaient plus de par un recidive par rapport a` ceux traites appareillage conventionnel
with “Invisalign” compared to those treated with the conventional appliances (Table VII). This result may be explained by the short duration of the active treatment (an average of 2 weeks between each splint), as well as the lack of torque and tooth axis control.
leve chez les patients traite s par « Invisalig » par rapport a` ceux e s par les appareillages conventionnels (Tableau VII). Ce traite sultat peut e ^tre explique par la courte dure e du traitement re re) actif (une moyenne de 2 semaines entre chaque gouttie ^le du torque et des axes ainsi que par le manque de contro dentaires.
Treatment with self-ligating devices
Traitement par les autoligaturants
Self-ligating appliances include a system of brackets for which many benefits have been claimed, particularly less friction and shorter treatment time, patient comfort and better outcomes [65–67]. Some searchers presumed a higher long-term stability using the self-ligating appliances due to de light generated forces, allowing a physiological movement of teeth [68]. In our systematic review, we found only one study comparing self-ligating brackets with the conventional system in terms of stability (Table VII). The author reported no significant differences between the two systems with an equal rate of incisor crowding relapse, due to the fact that both systems generate the same dimensional changes [69].
me d’attaches, dont Les autoligaturants constituent un syste te revendique s, notamment la de nombreux avantages ont e duction de la friction et de la dure e de traitement, le confort re riorite de ces re sultats [65–67]. Certains des patients et la supe sume d’une meilleure stabilite a` long terme chercheurs ont pre ^ce aux forces le ge res induites avec les autoligaturants gra placement physiologique des dents [68]. permettant un de matique, nous avons trouve une seule Dans notre revue syste tude comparant les attaches autoligaturantes aux attaches e (Tableau VII). L’auteur conventionnelles en termes de stabilite l’absence de diffe rence significative entre les deux a rapporte mes avec le me ^me taux de re cidive d’encombrement syste mes entraıˆnent les me ^mes incisif du fait que les deux syste changements dimensionnels [69].
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Incisor morphology
La morphologie des incisives
The size and diameter of incisors is one of the parameters, which have been widely investigated as factors involved in incisor alignment instability. The results and conclusions of these studies are various. In the study included in our systematic review, no correlation was reported between incisor morphology and mandibular crowding relapse [70] (Table VIII).
tre des incisives sont des parame tres qui La taille et le diame te e tudie s comme facteurs implique s dans ont largement e de l’alignement incisif. Les re sultats et les conclul’instabilite tudes sont varie s. Dans l’e tude incluse de notre sions de ces e matique, aucune corre lation n’a e te rapporte e revue syste cidive de l’encomentre la morphologie des incisives et la re brement mandibulaire [70] (Tableau VIII). une Smith et al. [71,72] ainsi que Doris et al. ont rapporte rence significative entre la taille des incisives et la survediffe cidive de l’encombrement mandibulaire avec une nue de la re rence dans la largeur me siodistale (MD) moyenne de diffe tudes semblables d’environ 0,25 mm par incisive. D’autres e aucune corre lation significative entre les dimenn’ont trouve cidive [73,74]. Peck et Peck [75] avaient sions des dents et la re re l’influence de la forme des incisives, en plus de leur sugge de leur alignement. Cependant, la taille, sur la stabilite de ces e tudes a e value une population non traite e majorite chantillon ont e te analyse s ou` seuls les moulages initiaux de l’e tudes ayant e value les changesans suivi a` long terme. Les e s de pose de la contention n’ont trouve ments a` long terme apre que des associations faibles ou inexistantes entre l’Indice gularite et la forme des incisives [73,74]. d’Irre
Smith et al. and Doris et al. [71,72] reported a significant difference between the size of incisors and the occurrence of mandibular crowding relapse, with a mean difference in the mesiodistal width (MD) of about 0.25 mm per incisor. Other similar studies found no significant correlation between tooth dimensions and relapse [73,74]. Peck and Peck [75] had suggested the influence of incisor morphology, in addition to their size, on the stability of their alignment. However, most of these studies assessed a non-treated population in which only the initial casts of the sample were analysed with no long-term follow up. The studies, which assessed the long-term changes after retainer removal, only found low or inexisting associations between the irregularity index and incisor morphology [73,74].
Quality of occlusion at the end of treatment
de l’occlusion de fin de traitement La qualite
Occlusion at the end of treatment is one of the parameters, which are strongly considered as a long-term stability factor [76–78]. However, recent studies have found no correlation between the quality of occlusal relationships and relapse [4,79–82].
tres largeL’occlusion de fin de traitement est un des parame re s comme facteur de stabilite a` long terme ment conside tudes re centes n’ont trouve [76–78]. Cependant, des e lation entre la qualite des rapports occlusaux aucune corre cidive [4,79–82]. et la re
Table VIII
Tableau VIII
tudiant la forme des incisives. Etude incluse e
Included study on incisor morphology.
Authors / Auteurs
Sample characteristics / Caracteristiques de
Conclusion / Conclusion
Freitas et al. [70]
56 patients (27 females and 29 males); class I or II malocclusions without DDD: dentodentaldiscrepency; fixed appliances; Edgewise mechanics extraction of the 4 first premolars; fixed retention 33–43 (1.63 W 1.19 years), posttreatment period (5.12 W 0.86 years) / 56 patients (27 femmes et 29
The morphological index of the mandibular incisor crowns is not correlated with long-term relapse of anterior mandibular crowding /
l’echantillon
L’index morphologique des couronnes des e avec incisives mandibulaires n’est pas correl la recidive a` long terme de l’encombrement mandibulaire anterieure
hommes) ; malocclusions de classe I ou II sans DDD ; appareillages fixes ; mecanique Edgewise ; extraction des 4 premieres premolaires ; contention fixe 33–43 (1,63 W 1,19 annees), periode post traitement (5,12 W 0,86 annees)
14
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Table IX
Tableau IX
Included study on the influence of dental occlusion.
Etude incluse traitant l’influence de l’occlusion dentaire.
Authors / Auteurs
Sample characteristics / Caracteristiques de
Conclusion / Conclusion
Freitas et al. [79]
87 patients, class I malocclusions treated with extraction of the 4 first premolars; Edgewise mechanics; divided into 2 groups according to the quality of their occlusion at the end of treatment: group 1 (n = 44 patients), group 2 (n = 43 patients) / 87 patients, malocclusions
Relapse of mandibular crowding was similar in de l’encombrement both groups / La recidive
l’echantillon
mandibulaire etait similaire dans les 2 groupes
avec extraction des 4 de classe I traitees premieres premolaires ; mecanique en 2 groupes selon la Edgewise ; divises qualite de leur occlusion de fin de traitement : groupe 1 (n = 44 patients), groupe 2 (n = 43 patients) Peer Assessment Rating (PAR); Irregularity Index (IIR) / Peer Assessment Rating (PAR) ; Index d’Irregularit e (IIR)
In this review, we found only one study investigating the impact of occlusion quality on the amount of crowding relapse [79] (Table IX).
une seule e tude e valuant Dans ce travail, nous avons trouve de l’occlusion sur la quantite de re cidive l’impact de la qualite de l’encombrement [79] (Tableau IX).
Limits
Limites
Our systematic review studied several factors, which have been associated for a long time with crowding relapse. Divergence in female patients, a thin cortical bone, and treatment with aligners have been associated with a higher rate of anterior mandibular crowding relapse. However, the heterogeneity of protocols between the different studies included in our systematic review, particularly the type of retention, the time period of wearing, the postretention period and the tools used to measure incisor crowding (Irregularity Index, TSALD, tooth size-arch length discrepancies) may explain the controversy of some results. Moreover, most of the studies present a low level of evidence with quite small sample sizes and a high rate of attrition. Therefore, it is impossible to identify evidence-based parameters responsible for mandibular incisor crowding relapse. Another limit of our review is the minimum follow up period of 3 years, which may be considered as limited for a study follow up. This minimum time of follow up period was selected in order to include a larger number of articles. Moreover, the follow-up period was included among the factors susceptible to affect stability.
matique a e tudie plusieurs facteurs qui ont e te Notre revue syste s a` la re cidive de l’encombrement. La pendant longtemps associe minin, une corticale fine divergence chez les patientes de sexe fe te associe s a` un taux plus et le traitement par les aligneurs ont e leve de re cidive de l’encombrement mandibulaire ante rieur. e du protocole d’e tude entre les Cependant, la variabilite rentes e tudes incluses dans notre revue syste matique diffe e de son port, la notamment le type de contention, la dure riode postcontention ainsi que les outils de mesure de pe Index, TSALD – tooth sizel’encombrement incisif (Irregularite arch length discrepancies) explique la contradiction de certains sultats. De plus, la majorite des e tudes pre sente un faible re chantillons relativement niveau de preuve avec des tailles d’e leve . Ceci rend impossible l’identipetites et un taux d’attrition e tres prouve s scientifiquement responsables fication des parame cidive de l’encombrement incisif mandibulaire. de la re riode minimale de suivi Une autre limite de notre revue est la pe ^tre conside re e comme limite e pour une de 3 ans, qui peut e tude de suivi. Le choix de ce temps minimal de suivi a e te fait e pour permettre l’inclusion d’un plus grand nombre d’articles. e du suivi a e te incluse parmi les facteurs En outre, la dure . susceptibles d’affecter la stabilite
Conclusion
Conclusion
Highlighting these results, it was not possible to give an evidence-based answer to the questions concerning indications
` la lumie re de ces re sultats, nous avons e te dans A de re pondre par la preuve scientifique aux l’impossibilite
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In order to obtain the best evidence for some factors, which may influence relapse, future reliable prospective studies are required to provide in the future unbiased and quantifiable results.
e d’une contenquestions portant sur les indications et la dure tres susceptibles tion mandibulaire. Plusieurs parame cidive de l’encombrement mandibulaire incisif d’impacter la re s un traitement orthodontique n’ont pas e te re ve le s dans apre sente revue syste matique, tels que les facteurs muscula pre laires, les facteurs locaux. . . Pour obtenir une meilleure preuve de l’effet de certains faccidive, des e tudes prospectives de qualite sont teurs sur la re cessaires afin de produire des re sultats objectifs et quantifine ables a` l’avenir.
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
and duration of mandibular retention. Several parameters susceptible in affecting relapse of the anterior mandibular incisor crowding after orthodontic treatment were not revealed in the present systematic review, such as muscular factors, local factors. . .
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