Impacted second molars, which surgical treatment choosing? / Absence d'évolution des deuxièmes molaires, quel traitement chirurgical proposer ?

Introduction: Delayed evolution of second molars is a rare phenomenon with an estimated prevalence in the mandible of 0 to 2.3%. Many etiologies have been proposed to explain these inclusions, among which the reduction of arch perimeter, distalization of first molar, mesio-angulated position of the second molar. However, the presence and position of the third molar does not seem to be a risk factor for this inclusion. Materials and Methods: Several therapeutics options with surgical management have been proposed in the literature; surgical repositioning, surgical release of the crown more or less associated with orthodontic treatment, and sometimes avulsion of the second molar to allow the third molar development. There is no recommendation on this subject, the literature describing mostly retrospective studies and case reports. Conclusion: This article presents the different therapeutic options in the treatment of second molar inclusions.

Introduction: Les retards d'évolution des deuxièmes molaires sont des phénomènes rares avec une prévalence estimée à la mandibule de 0 à 2,3 %. De nombreuses étiologies ont été proposées pour expliquer ces inclusions, parmi lesquelles la réduction du périmètre d'arcade, la distalisation des premières molaires, la position mésio-angulée de la seconde molaire. En revanche, la présence et la position de la troisième molaire ne semblent pas être un facteur de risque de cette inclusion. Matériels et méthodes: Plusieurs options thérapeutiques associant une prise en charge chirurgicale ont été proposées dans la littérature. Il s'agit du repositionnement chirurgical, du dégagement chirurgical de la couronne plus ou moins associé à un traitement d'orthodontie et parfois de l'avulsion de la deuxième molaire pour laisser évoluer la troisième molaire. Il n'existe pas de recommandation sur ce sujet, la littérature décrivant le plus souvent des études rétrospectives et des cas rapportés. Conclusion: Cet article présente les différentes options thérapeutiques dans le traitement des inclusions des secondes molaires.

Comparative study of excess glue around metallic APC™ Flash-Free adhesive system / Étude comparative des excès de colle autour des attaches métalliques préencollées APC™ Flash-Free

Introduction: The aim of this in vitro study was to determine if there is a significant difference in the excess adhesive flash between the metallic APC™ Flash-Free adhesive system, the APC™ pre-coated adhesive system and a conventional uncoated system. Materials and Methods: One hundred eighty-six freshly extracted human premolars were randomly and blindly divided into three groups according to the type of brackets. Group A (control group n=60): The conventional uncoated metallic bracket (Victory, 3M Unitek®) with a Transbond XT™ Light Cure Adhesive Paste was used. Group B (n=60): The APC™ II metallic maxillary precoated premolar brackets was used. Group C (n=66) : The metallic APC™ Flash-Free adhesive system without flash clean up was used. Images were taken at 40 magnifications in a dental microscope (Leica M320 for dental, Wetzlar, Germany) then analyzed with the ImageJ software and the area of excess adhesive flash was measured. Results: The mean percentage was significantly different between the three groups (p<0.001; ANOVA). It was significantly smaller for brackets in the APC Flash-Free group (p<0.001), and the difference was not significant between conventional brackets and APC (p=0.224). Discussion: The new technique seems to reduce the amount of excessive adhesive around orthodontic brackets.

Introduction: L'objectif de cette étude in vitro était de présenter une évaluation comparative et objective de l'efficacité d'une nouvelle technique d'attaches métalliques préencollées APC™ Flash-Free fabriquées par 3M Unitek®, éliminant l'étape de nettoyage grâce au système de fibres non tissées. Matériels et méthodes: Cent quatre-vingt-six prémolaires humaines saines fraichement extraites sont réparties en trois groupes de façon randomisée. Groupe A : 60 dents sont collées avec des attaches conventionnelles à encoller avec du Transbond XT™ (3M Unitek®). Groupe B : 60 dents sont collées avec des attaches préencollées APC™ II préenduites du même type de pâte adhésive. Groupe C : 66 dents sont collées avec des attaches APC™ Flash-Free (3M Unitek®), puis observées avec un microscope (Leica M320 for dental, Wetzlar, Germany) sous un agrandissement x40. Les photographies sont analysées à l'aide du logiciel ImageJ. Résultats: Les comparaisons multiples de Tukey ont montré que le pourcentage moyen était significativement plus petit au niveau des attaches du groupe C, APC™ Flash-Free (p-value<0,001), mais la différence n'a pas été significative entre les attaches conventionnelles du groupe A et celles préencollées du groupe B (p-value=0,224). Discussion: La technique de pointe adoptant un matériau non-tissé a l'air de réussir à réduire l'excès d'adhésif périphérique.

Evaluation of shear bond strength and adhesive remnant index of metal APC™ Flash-Free adhesive system: A comparative in vitro study with APC™ II and uncoated metal brackets.

OBJECTIVE: The aim of this in vitro study was to compare the shear bond strength (SBS) and the adhesive remnant index (ARI) of the metal APC™ Flash-Free adhesive system, the APC™ pre-coated adhesive system and a conventional uncoated system. MATERIALS AND METHODS: One hundred eighty-six freshly extracted human premolars were randomly divided into 3 groups and bonded by a single operator. Group A/Control Group (60 teeth): the manual bonding group treated with Transbond™ XT Light Cure Adhesive Paste (3M™ Unitek). Group B (60 teeth): treated with APC™II metal maxillary premolar precoated brackets. Group C (66 teeth): treated with metal maxillary premolar APC Flash-Free brackets. The teeth were then stored in distilled water at 37̊C for 24hours, and five hundred cycles of thermocycling were performed. The Shear Bond Strength (SBS) test was performed using an Instron Universal Testing Machine, and the adhesive remnant index (ARI) was determined using a dental optical microscope at ×25 magnification. RESULTS: The mean shear bond strength values showed differences between the three types of brackets (P=0.016; Anova). It was significantly higher with APC™II and lower with APC Flash-Free brackets; however, no significant differences were found between conventional and APC Flash-Free brackets (P-value=0.574). The distribution of the dichotomized ARI score was significantly different between the three brackets (P-value=0.049). The ARI score for APC Flash-Free brackets was higher with no significant difference between the conventional system and APC brackets (P-value=0.361). CONCLUSIONS: The mean SBS values were not significantly different between APC Flash-Free metal brackets and uncoated metal brackets. The APC Flash-Free metal system's bond failure occurred at the bracket-adhesive interface, with the highest percentage of teeth having more than 50% of the residual composite on the enamel after debonding.

[The orthognathic surgery so called « early ¼]. / La chirurgie orthognathique qualifiée de « précoce ¼.

Some young patients with a significant skeletal shift with a strong morpho-aesthetic and psychological impact may require surgical correction during their growth. A good understanding of facial growth, the different treatment options and the effects of surgery on the post-operative growth pattern will allow the practitioner to use the technique most suited to each of his patients and improve long-term treatment outcomes. So-called « interceptive ¼ surgery may therefore be considered in cases of severe skeletal dysmorphism of secondary or functional origin. It will lead to early normalization with the immediate consequence of breaking the « dysmorpho-dysfunctional ¼ spiral.

[What are the main surgical and non-surgical techniques of the acceleration of orthodontic tooth movement?] / Quelles sont les principales techniques chirurgicales et non chirurgicales de l'accélération du déplacement dentaire orthodontique ?

Different surgical and non-surgical techniques have been developed in order to reduce the duration of orthodontic treatment. Regarding surgical techniques, corticotomies are widely used. The micro-osteoperforation technique (MOP), in addition to the piezocision technique, have been developed to provide minimally invasive surgery as an alternative to conventional corticotomies, without the elevation of a mucoperiosteal flap. Regarding non-surgical techniques, the approach is radically different in terms of physical stimuli or chemical techniques. Corticotomy and piezocision techniques have been found to be effective in accelerating orthodontic tooth movement, although the corticotomy technique presents a significant risk of postoperative treatment. These two techniques also offer the possibility of adding a bone graft using a tunneling surgical approach. Regarding non-surgical techniques, physical stimuli techniques such as with a laser are easy to perform, non-invasive and seem to be promising. However, their effectiveness has not yet been demonstrated, as is the case for chemical techniques. While at first glance these techniques are reassuringly non-invasive, do they not give the sensation of playing the sorcerer's apprentice ? Although surgical techniques seem to have demonstrated their significant efficacy in accelerating orthodontic tooth movement, non-surgical techniques do not yet provide a sufficient level of evidence and / or safety to be performed in our routine clinical practice as orthodontists. As these topics are innovative, new and future scientific evidence should be able to lead to the development of all these concepts.

[Treatment is not diagnostic. Therapeutic common sense regarding class III dysmorphia]. / Traitement n'est pas diagnostic. Le bon sens thérapeutique face à la dysmorphie de classe III.

Class III dysmorphia, classically distributed in hereditary or functional etiology, have often multifactorial causes. Breaking the dysmorpho-dysfunctional cascade with early treatment may seem to be an essential alternative to give growth a new orientation. Whether the treatments are preventive, interceptive with or without an appliance, orthodontic or surgical (early, first-line or late), this takes more account of the clinical form than of age. The authors, through clinical cases, will develop their therapeutic approach, based on clinical common sense. Waiting to act at the right time is essential to set up treatments based on proven therapies.

Smartphone application-assisted oral hygiene of orthodontic patients: a multicentre randomized controlled trial in adolescents.

OBJECTIVE: The aim of this trial was to test whether the use of a smartphone application (app) connected to a toothbrush improves the oral hygiene compliance of adolescent orthodontic patients. DESIGN: The study was designed as a multicentre, randomized, controlled clinical trial. SETTING: Two academic hospitals. ETHICAL APPROVAL: The study was approved by the ethics committee. SUBJECTS AND METHODS: This multicentre randomized controlled trial was conducted on 38 adolescents aged 12-18 years with full-fixed orthodontic appliances. Participants were randomly assigned either to a test group that used an interactive oscillating/rotating electric toothbrush connected to a brushing aid app or to a control group that used an oscillating/rotating electric toothbrush alone. At baseline, all patients received verbal and written oral hygiene instructions. OUTCOME MEASUREMENTS: Data collection was performed at T1 (baseline), T2 (6 weeks), T3 (12 weeks) and T4 (18 weeks-end of the study). At each time point, the plaque index (PI), gingival index (GI) and white spot lesion (WSL) score were recorded. Several app-related parameters were evaluated. Patient-related outcome measures were investigated in the test group. RESULTS: Test and control groups were similar at baseline except for WSL score. Between T1 and T4, PI and GI decreased significantly in both groups but evolutions were globally similar in both groups. Interestingly, at T3 (12 weeks), the PI was significantly lower in the app group than in the control group (P = 0.014). Data showed a marked decline in the use of the app over time in the test group. CONCLUSIONS: This trial, conducted over 18 weeks in two academic hospitals, showed no significant effect of the use of the app in promoting oral hygiene. TRIAL REGISTRATION: Not registered.

Benefits of Digital Smile Design (DSD) in the conception of a complex orthodontic treatment plan: A case report-proof of concept.

INTRODUCTION: Digital Smile Design (DSD) is a systematic protocol based on specific photographs and software analysis that is used worldwide. DSD aims to assist the practitioner in creating and planning a course of treatment, especially in a multidisciplinary approach, and provides a virtual simulation of the final result. Additionally, it is a tool that enables communication and discussion between all the dental team, including the dental laboratory, and also with the patient. Although widely described and used in prosthetic rehabilitation, this tool remains only anecdotally used in the world of orthodontics. The objective of this proof of concept was to describe the application of the Digital Smile Design protocol in the diagnosis of orthodontic treatment. MATERIALS AND METHODS: A teenage patient was referred to our university clinic by a private orthodontic practitioner for a second opinion on the treatment at that time. The patient had a self-ligating orthodontic appliance. According to the history of the case and the oral situation at that moment, the patient required an accurately calculated plan for orthodontic tooth movement that would permit the achievement of future rehabilitation. Therefore, the decision was taken to use a DSD protocol to potentially complete the classic orthodontic examination. RESULTS: From the classic orthodontic examination, the patient presented a molar class I, midline deviations, the #21 and #23 were missing, #12 was conoid (microdontic) and, finally, #22 was in the position of #21. From the DSD results, three different views simulated the final results and therefore provided additional and relevant information, such as the correct position of the upper midline and the correct position of #12, #13, #22 and #23. CONCLUSION: This proof of concept showed the clinical relevance of the Digital Smile Design protocol as a new tool for complex orthodontic treatment planning, especially in a multidisciplinary approach. Further publications will be necessary in order to define a specific DSD protocol for orthodontic treatment.

[Accelerated orthodontic treatment using corticotomies: what are the minimally invasive alternatives?] / Traitement orthodontique accéléré par corticotomies : quelles sont les alternatives minimalement invasives ?

INTRODUCTION: The duration of orthodontic treatment in adults remains a barrier for some patients. Some surgical techniques have been developed in order to accelerate orthodontic tooth movement. The technique of corticotomies is effective in decreasing the orthodontic treatment time but remains invasive, leading to significant postoperative consequences. MATERIALS AND METHODS: Minimally invasive techniques without muco-periosteal flap elevation have been developed: corticision, micro-osteoperforations, piezopuncture and piezocision. RESULTS: The piezocision procedure seems to be the best compromise to accelerate orthodontic tooth movement while respecting a specific surgical and orthodontic protocol. The piezocision surgery allows the addition of biomaterials in cases of dehiscence and/or fenestration on the alveolar bone associated with moderate to severe overcrowding. CONCLUSION: According to current publications, minimally invasive corticotomy techniques can be viewed as a new therapeutic tool in the acceleration of orthodontic tooth movement.

Patient compliance and orthodontic treatment efficacy of Planas functional appliances with TheraMon microsensors.

OBJECTIVES: To assess patient compliance and treatment efficacy of preventive expansion treatment with removable Planas functional appliances using an integrated microsensor. MATERIALS AND METHODS: Wear time (WT) and behavior of 69 patients undergoing treatment with Planas functional appliances were assessed and analysed using TheraMon microsensors (Gschladt, Hargelsberg, Austria). Patients were followed up for a period of 9 months, and visits were made every 3 months to download WT data from the microsensor and to assess wearing behavior. From individual WT graphs,10 parameters were derived to characterize compliance for each patient. Treatment efficacy was measured by eight parameters determining the level of expansion after 9 months of treatment. RESULTS: Patients wore their device on average 15.8 ± 5.2 h/d. WT was unrelated to age and gender, but it was positively influenced by patient habits when keeping appliances during eating, sports, care and handling. Treatment efficacy in terms of intercanine and intermolar expansion was 4.4 ± 1.9 mm and 4.6 ± 2.0 mm for the maxilla, and 5.3 ± 2.0 mm and 4.7 ± 2.3 mm for the mandible, respectively. Efficacy was negatively affected by poor compliance (WT < 9 h/d) and by high variability of within-subject WT recordings. CONCLUSIONS: Perfect compliance is not necessary to achieve treatment success, but patients should exhibit sufficient wear time to allow maxillary expansion to occur. The TheraMon microsensor offers a new perspective and aid to individualize treatment prescriptions.

Selective piezocision-assisted orthodontic treatment combined with minimally invasive alveolar bone regeneration: A proof-of-concept.

BACKGROUND: Piezocision is a localised piezoelectric alveolar decortication involving minimally invasive corticotomies to accelerate orthodontic treatments. The objective of this proof-of-concept was to describe an innovative protocol combining selective piezocision with minimally invasive bone regeneration to reduce the risk of buccal tissue dehiscences often observed in orthodontic treatments. This proof-of-concept initial report aimed at investigating whether this new surgical concept is relevant. MATERIALS AND METHODS: A patient presenting an asymmetrical dental class II, overcrowdings, midline deviations and buccal bone dehiscences in the lower incisor region was treated with this new treatment approach. RESULTS: From an orthodontic point of view, the dental class II, the overcrowdings and the midlines were completely corrected. From a periodontal perspective, no gingival recession was observed; however, scars related to the piezocision were slightly visible at the mandible. The post-imaging demonstrated the absence of bone dehiscences. Up to 3 years after the completion of the treatment, no relapse was observed. CONCLUSION: This novel approach suggested several advantages and may be further investigated at a larger scale in order to validate the benefits and to define the scope of intervention.

Micrographic study and torsional strength of grade 23 titanium mini-implants recycled for orthodontic purposes.

INTRODUCTION: The aim of this study was to identify the fracture resistance of grade 23 Titanium mini-implants recycled for orthodontic purposes and having stayed in the mouth during different periods of time. MATERIALS AND METHODS: A total of 52 hybrid-designed titanium mini-implants, threaded length L=8mm, self-drilling and self-taping were used in 32 patients presenting orthodontic anomalies which required the use of mini-implants. Two types of tests were performed: polarizing optical imagery to assess the surface characteristics of the mini-implants (polarizing optical microscopy) and (mechanical) torsional strength tests, more quantitative, in order to establish the breaking point of the mini-implants during their re-use. RESULTS: For the mini-implants which had been in the mouth for a short period of time, (immediate removal or after two months of use), it must be noted that their surface characteristics revealed no defect at micron scale, the drilling head did not show any alteration, with a breaking point record of about 53Newton/cm2 (N/cm2). In contrast, the mini-implants, which had stayed in the mouth for 12 and 14 months, showed surface alterations especially at the "screw-gingiva" interface and the rupture stress ranges from 42 to 39N/cm2, respectively. DISCUSSION: Our results show that the resistance to fracture of the re-used mini-implants is inversely proportional to the duration of stay in the mouth.

[A perspective on the use of bone anchorage as opposed to other types of anchorage techniques]. / Mise en perspective de l'utilisation des ancrages osseux par rapport aux autres techniques d'ancrage.

INTRODUCTION: To convert our objectives into the desired treatment results, we need to control our mechanics and thus the anchorage used by avoiding any unwanted movements. It now seems unthinkable, at the dawn of the 21st century, to ignore the useful contribution of orthodontic screw-borne anchorage. Nevertheless, we are entitled to raise a number of legitimate questions. Do these forms of anchorage offer an alternative to all types of mechanics? Will they permit us to manage clinical situations which are beyond the scope of a more classical approach? Can they enhance the quality of our treatments? MATERIALS AND METHODS: Each of the authors describes clinical situations using screw-borne anchorage and compares with a conventional approach in order to make a non-exhaustive analysis of the mechanics applied, in their own office, and then highlights the most effective technique. RESULTS: With 15 years experience in the use of miniscrews, orthodontists have now adopted them with their many advantages as an integral item in their therapeutic armamentarium. However, treatment plans must be coherent. Our mechanics must be well thought-out and represent a cogent entity under the control of the practitioner. Creating screw-borne anchorage demands total control over anchorage stability.

[Reason for failure in the treatment of impacted and retained teeth]. / Échec de la mise en place de dents retenues et incluses.

The positioning of an impacted or retained tooth in either children or adults presents a real challenge for the two practitioners involved, the orthodontist and the surgeon in charge of the surgical exposure. The maxillary canine is the tooth most often impacted in the anterior segment, with a prevalence of 2% in the general population. One can understand, therefore, the functional and esthetic challenge for the surgical-orthodontic team whose aim will be to reposition the impacted or retained tooth in the arch. A large number of mistakes must be avoided in order to achieve a satisfactory result for both the patient and the practitioner. Modern imaging techniques should be used to obtain a precise diagnosis of the location of the tooth and to perform surgery which will spare the tooth in question as well as the surrounding anatomic structures. The directions and forces of the traction used will need to be carefully thought out in order to move the tooth into its final position on the arch in optimal conditions. The periodontal setting will be optimized and checked at every step of the treatment. The aim, in fact, is to anticipate the onset of periodontal problems on the grounds that prevention is easier than cure.

[Alveolar bone thickness in A point area : how to avoid periodontal failures in front of upper incisors]. / Épaisseur d'os alvéolaire dans la zone du point A : savoir éviter les échecs parodontaux en regard des incisives maxillaires.

Studies on orthodontic-periodontics relationships are numerous but few have benefited from the contribution of new 3D imaging techniques that emphasize iatrogenic effects that orthodontics may have on the periodontium. Periodontal risk in terms of fenestration, bone dehiscences next maxillary incisors are real during or after orthodontic treatment. The accurate assessment of the initial situation in terms of bone quantity in this dental arch anterior segment is thus very important. Our study aimed to evaluate the reliability of conventional lateral cephalograms to quantify alveolar bone thickness in relation to the maxillary incisors by comparing it with data from CT scans. The second objective was to identify an at risk patient profile by assessing possible correlations between this thickness and dysmorphia components. The results revealed a half of assessment error in the estimation of bone thickness and increased risk in case of hyperdivergence typology, Class III skeletal relationships and dento-alveolar protrusion. Finally, in view of these data, we discussed the clinical procedures to avoid such periodontal failures in this anterior segment of the dental arch.

[Failure in anterior rehabilitation of agenesic maxillary lateral incisors]. / Échec dans la réhabilitation antérieure en cas d'agénésies des incisives latérales maxillaires.

Agenesis of the maxillary lateral incisors poses particular problems for dentists, orthodontists and patients. Treatment of these ageneses is still highly controversial, both functionally and esthetically. The patient's smile and anterior guidance are affected and must be restored. The diagnosis is easy. Few mistakes are possible. However, managing patients with missing maxillary lateral incisors can be a challenge, commonly involving two possible treatment approaches: space opening to replace the missing lateral incisor with a prosthetic unit (denture, bridge or implant) or orthodontic space closure replacing the missing lateral incisor with the maxillary canine camouflaged to mimic the appearance of a lateral incisor. One of these two options will be adopted using multiple means...liable to trigger a multitude of possible errors. Ultimately, optimal results can only be achieved if there is excellent coordination between different practitioners in various specialties. Each clinician will have a specific role to play. Also, the patient and family are at the heart of the decision-making process, by virtue of their consent (treatment duration, financial resources) and their motivation. This multi-factorial, multi-disciplinary decision process means that treatment of the lateral incisor is an ongoing challenge for the clinician striving for the best possible result. Each case is different. No set rules exist. No single factor can be neglected if we are to avoid "failure".