Orthodontic brackets debonding: evaluation of the time factor and the tooth type / Décollement des attaches orthodontiques : évaluation du facteur temps et du type de dent

Introduction: The aim of the study was to assess the time factor and tooth type during premature debond of orthodontic brackets. Material and Method: A retrospective epidemiological study was carried out on adolescents who had benefited from a multi-metal vestibular attachment treatment, having all 6 to 6 teeth bonded to the arch on the day of installation. Results: 333 patients were included. The detachment rate decreased as the treatment progresses. The teeth with most orthodontic debonding were the maxillary first molar, mandibular first molar, mandibular second premolar, and maxillary second premolar. Skeletal class II patients tended to take off more than class I patients. Detachments were significantly more frequent in the mandibular arch in deepbite compared to normalbite patterns, the mandibular second premolar being the tooth at risk. There seems to be a correlation between the quality of oral hygiene and the rate of detachment, regardless of the time of treatment. Discussion: The type of orthodontic movement, the quality of the bonding, the failure to observe the precautions by the patient may affect the date of the detachment. The low coronary height, hygiene, the biting force, the divergence seems to intervene on the type of attachment debonded. Conclusion: The brackets are more particularly debonded at the start of treatment and on the posterior teeth. Anteroposterior and especially vertical dysmorphosis could have an implication in debonding.

Introduction: L'objectif de l'étude était d'évaluer le facteur temps et le type de dent lors du décollement prématuré des attaches orthodontiques. Matériel et méthode: Une étude épidémiologique rétrospective a été réalisée sur les adolescents ayant bénéficié d'un traitement multi-attache vestibulaire en métal, ayant toutes les dents collées de 6 à 6 sur arcade le jour de la pose. Résultats: Au total, 333 patients ont été inclus. Le taux de décollement diminuait au fur et à mesure du traitement. Les dents avec le plus de décollements d'attaches orthodontiques étaient la première molaire maxillaire, la première molaire mandibulaire, la deuxième prémolaire mandibulaire et la deuxième prémolaire maxillaire. Les patients en classe II squelettique ont tendance à davantage décoller que les patients en classe I. Les décollements étaient significativement plus fréquents à l'arcade mandibulaire chez les hypodivergents que chez les mésodivergents, la deuxième prémolaire mandibulaire étant la dent à risque. Il semble exister une corrélation entre la qualité de l'hygiène buccale et le taux de décollement, quel que soit le moment du traitement. Discussion: Le type de déplacement orthodontique, la qualité du collage, le défaut d'observance des précautions par le patient peuvent intervenir sur la date de décollement. La hauteur coronaire faible, l'hygiène, la force de morsure, la divergence semblent intervenir sur le type d'attache décollé. Conclusion: Les attaches sont plus particulièrement décollées en début de traitement et sur les dents postérieures. Les dysmorphoses antéro-postérieures et surtout verticales pourraient avoir une implication dans le décollement.

[What are the risk factors specific to patient for debonding of orthodontic brackets?] / Quels sont les facteurs de risque de décollement des attaches orthodontiques propres au patient ?

The premature detachment of orthodontic brackets has consequences for the patient and the practitioner. While the responsibility for the bonding protocol has been widely assessed, the responsibility of the patient is poorly understood. The main objective of the study was to look for patient-specific predictors of metal vestibular attachment detachments. An historical cohort study was carried out from adolescents having benefited from a fixed vestibular appliance treatment lasting 27 months +/- 3 months, having all teeth from first molar to first molar on arch to pose. Univariate and multivariate analyses were performed by logistic regression. 333 patients were included. In univariate analysis, boys tended to take off more than girls, patients in skeletal Class II more than those in Class I, those with at least two cooperative remarks more than those with less than two remarks. The percentage of patients with debonding increases with the number of hygiene remarks. Younger patients were more prone to debond than older patients. The "age" factor has a significant effect in multivariate analysis. Neither the vertical skeletal pattern nor the socio-economic level would intervene in the rate of debonding. The role of patient-specific factors in detachment should be put into perspective. The reliability of the results would be increased by a prospective study using validated indicators of compliance.

[Miniscrews during the retention phase: indications, therapeutic means and effects]. / Les minivis pendant la phase de contention : indications, moyens et effets thérapeutiques.

Even if miniscrews are mainly used in the active phase, their uses during the contention have been reported for a few years either by installation of miniscrews de novo or by taking advantage of miniscrews inserted during the active phase. The objective of this article is to describe the uses - reported in the literature - of miniscrews during the retention phase. We have conducted a research from the database PubMed with keywords associations. Nineteen articles were found with three indications: to temporarily replace toothlessness while awaiting the final prosthetic solution at the end of growth while maintaining bone level; to contain open-bite treatments in order to avoid as much as possible the relapse; to improve the comfort and aesthetics of Hawley plate. This prospect of using miniscrews after active treatment further opens up the field of possibilities. However, there is the problem of osteointegration and bone damage caused by the removal of miniscrews linked to the maintenance of miniscrews over the long term.

[What are the factors influencing the aesthetic requirement in the choice of orthodontic appliances in adults?] / Quels sont les facteurs influençant l'exigence esthétique dans le choix du dispositif orthodontique chez l'adulte ?

Although adult patients are said to be demanding in terms of discretion of the orthodontic appliance, the factors influencing the choice of the appliance are still poorly understood. The main objective of this study was to determine if there is a correlation, in adults, between the importance of the orthodontic treatment need and the aesthetic preference of the orthodontic appliance (metal braces, ceramic braces in buccal, lingual or aligner). The secondary objectives were to evaluate the impact of the patient's personal factors, his eventual orthodontic past and his perceived orthodontic need. Patients were interviewed by questionnaire before the first consultation. An index, depending of the discretion of the appliance, was used. The need for treatment was calculated via dental health component and aesthetic component of IOTN. Given the size of the sample, only trends can be emitted. The real need for treatment had no influence on the choice of the aesthetic appliance. The most demanding patients would be women, in their thirties, single, employed, executive or practicing a higher profession, with previous orthodontic treatment and having recently consulted an orthodontist, as an adult. These patients felt that their orthodontic treatment need was minimal or significant. Patients estimated the duration of treatment at 17 months. Lingual was considered the most aesthetic appliance far ahead of the aligners. A larger scale study is needed to determine the influence of each factor.

[Biomechanics of mini-implants : analysis of the adverse effects of four clinical situations and proposed resolutions]. / Biomécanique des mini-implants : analyse des effets parasites de quatre situations cliniques et propositions de résolutions.

The biomechanical adverse effects generated by our treatments must be considered among the failures of mini-implants, certainly excellent means of anchorage. The aim of this article was to illustrate and comment on mechanical adverse effects and to propose solutions. Four common clinical situations in vestibular technique are analyzed, decomposed three-dimensionally and solved. Maxillary incisor intrusion in direct traction (mini-implant between lateral incisors and canines in direct anchorage) can lead to a disto-labial rotation of the supporting teeth and an incisor flaring. Maxillary incisivo-canine retraction (mini-implant between 5 and 6 in direct anchorage) leads to a canine rotation, a clockwise rotation of the occlusal plane and a version of the adjacent teeth. The maxillary molar two-steps distalization (mini-implant between 5 and 6 with metal ligation to the canine) causes a rotation of the adjacent to the spring teeth, an incisor flaring and a molar disto-version. The protraction of a mandibular molar (mini-implant between 3 and 4 in direct anchorage) causes a disto-labial rotation, a lingual torque and a mesio-version of the molar as well as an incisor flaring and a clockwise rotation of the occlusal plan. The compensation bends on the adjacent teeth, the choice of the location and the type of mini-implant, the use of a power arms to get closer to the center of resistance are among the means of resolution. If mini-implants anchorage allows a significant quantitative effect, adverse effects should be considered individually with a three-dimensional biomechanical analysis.

[Brackets positioning errors and available solutions. A review of the literature]. / Erreurs de positionnement des boîtiers et solutions disponibles. Une revue de la littérature.

Due to many innovations, bonding in the sense of bracket positioning is continually remodeling itself. Therefore, we wanted to define what a good bonding was and how to achieve it, both by identifying factors that could alter it and by evaluating the bonding assistances currently available. We carried out the synthesis of 65 comparative studies from PubMed. The inter-individual variations in dental morphologies are greater than the differences in the prescriptions available for the brackets. Tweed's bonding procedure at constant heights alters the leveling of the marginal ridges of the posterior teeth. The gauge improves the vertical positioning of the brackets, regardless of the clinician's experience. There is no clinical evidence to a superior efficiency of individualized techniques. The prescriptions of Mc Laughlin and Bennettseem more aesthetic than those of Andrews for the anterior teeth. The avail of indirect bonding is not obvious. Individualization is necessary in lingual technique, but does not allow better results in vestibular technique compared to conventional standardization. Evolutions are to be expected with the modeling of the individual biological response to induced tooth movement. While digital assistance is promising, it does not replace the expertise of the orthodontist.