L'' Orthodontie française最新文献

Introduction: This study aimed to determine the vertical and horizontal soft-tissue vs hard-tissue changes after isolated functional genioplasty and to revisit hard-tissue remodeling at the symphysis.

Methods: Seventy-five patients who underwent genioplasty as an isolated procedure at the end of their orthodontic treatment were divided into three groups on the basis of their age at surgery: < 15 years (group 1), 15-18 years (group 2) and ≥ 19 years (group 3). Patients were evaluated at three time points: immediately before surgery (T1), immediately after surgery (T2) and two years after surgery (T3). In addition, 25 patients who did not accept genioplasty, were age-matched with group 1, and had a follow-up radiograph two years after the end of their orthodontic treatment were used as a control group.

Results: From T2 to T3, group 1 showed less forward horizontal hard-tissue and soft-tissue changes at pogonion (Pg) than the control group; however, no difference was noted for vertical changes at Me & Me’. From T1 to T3, the horizontal hard-tissue and soft-tissue changes at Pg were 6.39 mm and 6.72 mm, respectively, for surgical groups. Vertical hard-tissue change at menton (Me) showed a reduction of 1.63 mm (95% confidence interval [CI], -3.37 to 0.11) and 3.89 mm (95% CI, -5.83 to -1.95) in nongrowing female and male patients, respectively. The vertical soft-tissue change reduction was similar for nongrowing male and female patients (1.7 mm [95% CI, -2.96 to -0.45]). Soft-tissue thickness change at Pg (0.33 mm) was not significant. In contrast, a small but significant increase in soft-tissue thickness was noted at Me (0.54 mm). Linear regressions were calculated for all groups and allowed for predicting long-term soft-tissue changes (T3-T1) using the amount of surgical displacement (T2-T1).

Conclusions: The horizontal hard-tissue change was stable for nongrowing patients, and the horizontal soft-tissue change was 92% of hard-tissue. Vertical soft-tissue change is less predictable. Variation of soft-tissue thickness after genioplasty can be explained by skeletal changes and the achievement of an unforced labial occlusion. These results support the functional and esthetic benefits of this surgery. Comparison with the control group showed that genioplasty does not change the growth pattern, and bone remodeling is likely to explain the difference noted at Pg.

Introduction: The choice of composite type is an important factor and can affect the success of treatment. The aim of this study was to compare the failure rate of two light-curing composites and to evaluate the effectiveness of each in vivo. The two composites studied were Transbond XT® (3M®) and BracePaste® (American Orthodontics®).

Material and method: An analytical, experimental, longitudinal and prospective study was conducted. A sample of 22 patients with a total of 440 teeth was selected. The decemented brackets were considered from the central incisor to the second premolar. A software was used to randomly distribute the type of adhesive according to the right and left side of the patient. Thus, Transbond XT® was used in two quadrants and BracePaste® in the other two. Braces that were not decemented after six mounths were considered successful.

Results: Four failures with BracePaste® and three with Transbond XT were observed. These are respectivly 18.2% vs 13.6% among the 22 patients and 0.9% vs 0.7% among the 440 teeth (p>0.05).

Discussion: Many studies have tested the efficacy of adhesives in vitro and many have failed to predict in vivo efficacy. Therefore, the aim of our study was interesting.

Conclusions: In our sample, no difference in bonding failure was observed between Transbond XT® and BracePaste®.

Objective: To compare dentoskeletal changes produced by the maxillary splint headgear and cervical headgear appliance during the early phase of Class II treatment, specially the initial overjet and upper incisors position.

Subjects and methods: In this retrospective study, 28 Class II patients treated with the maxillary splint headgear (maxillary splint headgear or MSG, mean age 10.1 ± 1.9 years) and 28 Class II patients treated with cervical headgear (cervical headgear group or CHG, mean age 9.5 ± 1.9 years) were evaluated before and after treatment. Statistical comparisons between the two groups for cephalometric measurements at T1 and for T2-T1 changes were performed by means of independent sample t tests.

Results: The MSG showed a significantly greater reduction of the overjet in comparison to the CHG (-2.4 mm and -0.7 mm, respectively) and a significantly greater maxillary incisor uprighting (-1.8 mm and 0.4 mm, respectively). In the MSG, overjet correction was due mainly to mandibular advancement (3.5 mm), while the correction of molar relationship (3.9 mm) was 64% skeletal and 36% dentoalveolar. In the CHG, the overjet correction was also more skeletal, due to mandibular growth (1.8 mm), while correction of molar relationship (3.5 mm) was 63% dentoalveolar and 37% skeletal.

Conclusions: Both groups showed favorable skeletal mandibular changes, which was more significant in the MSG. Regarding tooth movement, the maxillary splint headgear was more effective in uprighting upper incisors and reducing the overjet than cervical headgear appliance.

Introduction: Orthognathic surgery aims to treat facial dysmorphoses related to an anomaly of the maxillomandibular complex. This surgical treatment is most often performed in parallel with orthodontic treatment for functional and aesthetic purposes. In order to provide more efficient management and obtain a better stability of result, simple procedures must be added to orthognathic surgery to treat chronic nasal obstruction (CNO).

Materials and methods: The authors describe the techniques for surgical correction of CNO during orthodontic-surgical treatment and illustrate with some clinical cases.

Conclusions: Restoration of nasal ventilation should be an objective of orthodontic-surgical treatment. CNO treatment can be performed at the same time as a maxillomandibular osteotomy.

Introduction: The number of adult patients who seek an orthodontic treatment is increasing. These Primary failure of eruption (PFE) is defined as the partial or complete failure of eruption of at least one posterior tooth, without any mechanical obstacle. A better understanding of the biological mechanisms involved in PFE would enable to refine the diagnostic and prognostic criteria. This rare disease is currently related to PTHR1 gene variants. This gene codes for a transmembrane receptor involved in bone metabolism. However, there is few evidence associating PFE and bone remodeling abnormalities such as external root resorption. External root resorption is the loss of cementum and dentin tissues, resulting from the activation of clastic cells.

Materials and methods: Human teeth affected by PFE were extracted and histological sections were made after fixation of the tissues in 4% PFA. The observations were correlated with three-dimensional imaging by cone beam computed tomography (CBCT) carried out in the preoperative phase.

Results: Histological and radiographic analysis confirm the presence of ankylosis area in patients with no history of orthodontic treatment. Large areas of resorption of external root replacement were detected.

Discussion: The results call the causal link between the appearance of ankylosis areas and the establishment of orthodontic traction in patients with PFE into question. The installation of an orthodontic force in this context could be only an aggravating factor, accelerating the processes of ankylosis or triggering them more prematurely.

Conclusion: With or without orthodontic treatment, teeth with PFE are likely to progress to ankylosis and resorption of replacement external root.

Introduction: The number of adult patients who seek an orthodontic treatment is increasing. These patients often have lithium disilicate ceramic restorations. The orthodontist has to find a procedure to bond effectively brackets to these restorations. In 2011, a new family of adhesives was introduced, universal adhesives, which are capable of bonding to ceramic and are said “multi-mode” because they can be used in etching-rinse or self-etching protocol on tooth surface. The objective of this in vitro study was to evaluate the shear bond strength (SBS) of metal brackets to lithium disilicate ceramic support using a universal adhesive.

Materials and methods: Forty machinable lithium disilicate blocks (IPS e.max CAD, Ivoclar) were prepared according manufacturer’s instructions. Each specimen was randomly assigned to one of four groups (n=9 or 10) defined by the pretreatment protocol. Protocol 1: Hydrofluoric Acid 9 % (HF) + Silane + Orthodontic adhesive (Transbond™ XT Light Cure Adhesive Primer, 3M ESPE), protocol 2: HF + Universal adhesive (UA) (Scotchbond Universal®, 3M ESPE), protocol 3: UA only, protocol 4 : Monobond Etch & Prime® (Ivoclar) + UA. Then, a bracket of upper cuspid (3M ESPE) was bonded to each specimen with a composite resin (Transbond™ XT, 3M ESPE). SBS was measured between ceramic and bracket with a universal testing machine. A one-way ANOVA (ANalysis Of Variance) followed by Tukey’s post-hoc test was performed to investigate SBS differences between groups.

Results: Protocol 2 (43 MPa) and protocol 4 (36 MPa) showed the highest SBS values and were statistically different from protocol 1 (25 MPa) and protocol 3 (21 MPa).

Conclusion: Despite the lower bond values obtained in the study, but higher than the minimum expected, the application of UA alone appears to be a safe procedure that seems to provide sufficiently strong and resistant bonding between the ceramic and the bracket. However, clinical studies are needed before a recommendation can be made.

Introduction: Plaque control remains a concern in oral health but also in orthodontics.

Objective: The aim of this paper was to investigate the dental plaque adhesion to different orthodontic appliances.

Materials and methods: Four literature reviews were initiated to clarify the accumulation of dental plaque to different orthodontic appliances, namely the type of brackets (conventional versus self-ligating, metal versus clear), the type of ligatures (metal versus elastomeric) in addition to the type of archwires. Moreover, a gallery of Scanning Electron Microscopy (SEM) images was made on different orthodontic appliances before and/or after time in the oral cavity.

Results: Considering the strong methodological heterogeneity of the included studies, there is no consensus on which type of bracket should be preferred for the prevention of plaque retention. Metal ligatures would be less prone to plaque accumulation compared to elastomeric ligatures, which are themselves color-dependent. The type of archwire was not investigated in this topic. SEM images highlighted the presence of anfractuosities on the surface of new orthodontic archwires as well as the presence of biofilm at different degrees of maturation on the appliances after time in the oral cavity.

Conclusion: Although it is not possible to establish a consensus on which orthodontic appliances should be preferred to decrease plaque retention, different stages of biofilm evolution are observable on their surface and therefore potentially associated with a proportional virulence.

Introduction: Molar protraction can be used in several clinical situations. It provides a real service to the patient, when it makes it possible to replace an implant, for example, or in case of a very damaged molar compared to the patient’s age.

Material and method: In this article, the authors describe the different molar mesialization systems in the vestibular multi-attachment technique, outlining the biomechanics of each.

Discussion: The mini-screws introduction in the practices has made it possible to improve the anchorage management, which is essential in this therapy. However, it is not always offered, depending on the patient’s wishes, but also sometimes of the orthodontist’s.

Conclusion: The different biomechanical situations analyzed each have their own characteristics, advantages and disadvantages. A methodical reflection must lead the practitioner to choose the system that suits him, according to his experience and practice, in order to implement this therapy for the well-being of his patients.

Introduction: The aim of this study was to evaluate the impact of nasomaxillary expansion using skeletally anchored transpalatal distraction (TPD) in children without transverse maxillary deficiency that were previously treated by rapid palatal expansion (RPE).

Materials and methods: Twenty-nine consecutive children were treated by TPD. Twenty-five children, aged 10-16 years completed pre- and post-operative clinical evaluations, questionnaires (OSA-18), cone beam computed tomography (CBCT), and polysomnography (PSG). The pre- and post-operative CBCT data were used to reconstruct the 3-dimensional shape of the upper airway. Two measures of airflow function (pressure and velocity) were simulated by using computational fluid dynamics (CFD) at four different airway segments (nasal, nasopharyngeal, oropharyngeal and hypopharyngeal).

Results: Twenty-three patients (92%) experienced improvement based on PSG. The apnea hypopnea index (AHI) improved from 6.72 ± 4.34 to 3.59 ± 5.11 (p<0.001) events per hour. Clinical symptoms based on OSA-18 scores were improved in all patients. Twenty-five patients (100%) had successful expansion defined as separation of the midpalatal suture at least 1mm from anterior nasal spine (ANS) to posterior nasal spine (PNS). The nasal sidewall widening was 2.59 ± 1,54 mm at canine, 2.91 ± 1,23 mm at first molar and 2.30 ± 1,29 mm at PNS. The ratio of dental expansion to nasal expansion was 1.12:1 (2.90mm:2.59mm) at canine and 1.37:1 (3.98mm:2.91mm) at first molar. The nasal airflow pressure reduced by 76% (-275.73 to -67.28 Pa) and the nasal airflow velocity reduced by over 50% (18.60 to 8.56 m/s).

Conclusions: Nasomaxillary expansion by skeletally anchored TPD improves OSA in children without transverse maxillary deficiency that were previously treated by RPE. A nearly parallel anterior-posterior opening of the mid-palatal suture achieves enlargement of the entire nasal passage with improvement of the airflow characteristics in the nasal and pharyngeal airway. The improved airflow characteristic is significantly correlated with the improved polysomnographic findings, thus demonstrating that nasomaxillary expansion in previously expanded patients is a viable treatment option.

Aim: Class II extraction approach by means of maxillary first premolars represents a common treatment strategy in order to reduce the overjet and create a stable Class I canine relationship and Class II molar relationship. The objective of this paper is to describe digital planning protocol and complete clinical phases of space closure in Class II malocclusion treatment in adult patient.

Materials and methods: The accuracy of movements and correction of dental parameters has improved exponentially in recent years, as a result of continuous research performed in aligner orthodontics. However, the most complex movement to realize with aligners is the apical movement, but the application of the G6 protocol for managing extractive cases allows to obtain the final parallelism of the roots with a control of the tipping managed on the digital plan as an overcorrection (overtipping) of the roots adjacent to the extraction site. Through the description of two cases, this article will present the application of the specific protocol for first premolars extraction in order to manage anchorage and closure of extraction spaces.

Results: All patients finished with proper OVJ and OVB with a Class II molar relationship and Class I canine relationship respecting face balance and smile arc.

Discussion: The Invisalign G6 protocol through the use of SmartStage™ technology combined with SmartForce™ features provides vertical control during anterior sector retraction and teeth body movement maintaining maximum posterior anchorage.