Treatment stability with bonded versus vacuum-formed retainers after 12 months: A randomized clinical trial.

OBJECTIVE: To compare the clinical effectiveness of V-bend bonded retainers (BR) versus vacuum-formed retainers (VFR) regarding their capacity to maintain treatment stability and survival rates after 12 months. MATERIALS AND METHODS: Patients finishing orthodontic treatment were randomly allocated into two groups. The BR group received maxillary and mandibular BRs in the lingual surfaces of the anterior teeth. The VFR group received VFRs right after fixed appliances removal. The patients were evaluated at four time-points: at fixed appliances removal (T0), after 3 (T1), 6 (T2) and 12 months (T3). In each time-point digital models were obtained and analysed with the OrthoAnalyzer™ software. Treatment stability based on occlusal outcomes and retainers' survival rates were evaluated. Intergroup comparisons were performed using Mann-Whitney U-tests. The Kaplan-Meier survival plot and the log-rank test were employed to assess the retainers' survival. RESULTS: Both BR and VFR groups included 25 patients. The groups were comparable regarding their baseline characteristics. Up to 6 months, both retainers were equally effective; however, after 12 months, BRs were more effective in maintaining the incisors' alignment in the maxilla and the mandible compared to the VFRs. No differences were noticed in the intercanine and intermolar widths, overjet and overbite. There were no differences regarding the retainers' survivability in both arches. CONCLUSIONS: BRs were more effective in maintaining the alignment of the incisors in the maxilla and mandible compared to VFRs after 12 months. Both retainers presented the same survival rates after the same period.

Treatment of Class II malocclusion with 2-maxillary premolar extractions: Monthly vs biweekly appointments, which is more efficient?

INTRODUCTION: This study compared whether there is a difference in treatment time (TT) and efficiency when appointments are held once a month or at 2-week intervals in patients with Class II malocclusion treated with 2-premolar extractions METHODS: The patients of this retrospective sample were treated with the same orthodontic mechanics and divided into 2 groups according to frequencies of orthodontic appointments. Group 1 consisted of 18 patients (10 males, 8 females), with an initial mean age of 14.38 ± 1.38 years and appointments once a month. Group 2 consisted of 19 patients (9 males, 10 females), with an initial mean age of 14.12 ± 1.38 years and biweekly appointments. Edgewise fixed appliances with a slot size of 0.022 × 0.028 mm were used, and the anterior teeth were retracted en-masse with a rectangular wire and elastic chains. The Peer Assessment Rating and Objective Grading System indexes were measured in the dental models at the beginning and the end of treatment. Efficiency was assessed by dividing the percentage of improvement of each occlusal index concerning the multiplication of TT and the number of appointments. RESULTS: Both groups presented similar Peer Assessment Rating and Objective Grading System indexes at the end of treatment. Groups 1 and 2 presented different TTs (28.06 and 22.05 months, respectively); however, there were no differences regarding the efficiency of both protocols. CONCLUSIONS: Patients with Class II malocclusion treated with 2-maxillary premolars had significantly shorter treatment times when seen on biweekly appointments than those with monthly appointments; however, there was no difference in efficiency between protocols.

Self-correction of the ectopic eruption of the maxillary first permanent molar and its predictive factors: A systematic review.

BACKGROUND: Ectopic eruption of the maxillary first permanent molar is a local disturbance that affects the development of the occlusion. AIM: To evaluate the occurrence of self-correction of maxillary first permanent molar's ectopic eruption and its predictive factors. DESIGN: Five electronic databases and part of the gray literature were investigated. The risk of bias was assessed using the Newcastle-Ottawa scale and the certainty of evidence using the GRADE tool. RESULTS: Four studies were selected: Three had a low risk of bias, and one, moderate. Evidence with a moderate level of certainty was generated, indicating a possibility of 47%-78% of spontaneous correction up to 7 years of age. Supporting the prognosis, whether reversible or irreversible, there was a positive correlation between the severity of the atypical distal resorption of the second primary molar, a higher magnitude of impaction, a larger eruption angle, and a bilateral occurrence with the irreversibility of the cases. CONCLUSION: Spontaneous correction of the ectopic eruption of the maxillary first permanent molar is feasible and dependent on the severity of predictive factors. Early intervention is mandatory in irreversible cases.

Twin-block and mandibular anterior repositioning appliances effects in Class II malocclusion correction.

INTRODUCTION: The objective of this study was to compare the cephalometric changes in Class II Division 1 malocclusion patients treated with the Twin-block (TB) and the mandibular anterior repositioning appliance (MARA). METHODS: This retrospective study was performed with 132 lateral cephalograms of patients with Class II malocclusion divided into 3 groups: a TB group comprised 21 patients with mean initial and final ages of 10.59 and 11.97 years, respectively, treated for a mean period of 1.38 years; a MARA group comprised 21 patients with mean initial and final ages of 11.98 and 13.20 years, respectively, treated for a mean period of 1.22 years; and a control group included 24 subjects with untreated Class II malocclusion with mean initial and final ages of 10.55 and 12.01 years, respectively, observed for a mean period of 1.46 years. Cephalometric intergroup comparisons regarding the treatment changes (T2 - T1) were performed with the analysis of covariance, followed by Tukey tests. RESULTS: Both appliances demonstrated significant restriction of the maxilla and improvement of the maxillomandibular relationship. The MARA produced a significantly greater amount of labial tipping and protrusion of the mandibular incisors than the other groups. The TB showed significant extrusion of the mandibular incisors and molars compared with MARA and control, respectively. Both treated groups reduced the overjet and overbite. The MARA presented a significantly greater reduction in the molar relationship than the other groups. CONCLUSIONS: The appliances showed a headgear effect on the maxilla and effectively changed Class II cephalometric parameters through a combination of skeletal and dentoalveolar effects. TB showed a greater increase in LAFH. MARA promoted greater labial tipping and protrusion of the mandibular incisors.

Root resorption in Class II malocclusion treatment with and without maxillary premolar extractions.

INTRODUCTION: Class II malocclusion treatment efficiency with maxillary premolar extractions has been reported. However, no study evaluated the root resorption associated with this protocol. Therefore, this study aimed to compare the degree of root resorption of the maxillary incisors in Class II malocclusion treatment with and without maxillary premolar extractions. METHODS: The sample consisted of 56 patients with complete Class II malocclusion, divided into 2 groups. Group 1 comprised 28 patients (10 female, 18 male) treated with maxillary first premolar extractions, and group 2 was composed of 28 patients (16 female, 12 male) treated without extractions. The groups were matched regarding initial age, treatment time, crowding, initial malocclusion severity, finishing quality, initial overjet, and overbite. Periapical radiographs of the maxillary incisors were used to assess the degree of root resorption using a scoring system. In addition, treatment changes involving maxillary incisors were evaluated in lateral headfilms. Intergroup comparisons were performed with t, Mann-Whitney U, and chi-square tests (P <0.05). RESULTS: Overjet, overbite, inclination, vertical positional changes, and vertical and horizontal apical displacements of maxillary incisors were similar between groups. There was no statistically significant difference between groups regarding root resorption of maxillary incisors. Root resorption degree ranged from mild to moderate in both groups. CONCLUSIONS: Treating complete Class II malocclusion with 2 maxillary premolar extractions resulted in a similar root resorption as treating without maxillary premolar extractions. An individualized evaluation of root resorption predisposing factors should be performed for each patient.

Dentoskeletal and soft-tissue changes of class II malocclusion treatment with modified first class appliances: a prospective clinical trial.

BACKGROUND/OBJECTIVES: Intraoral distalizers are effective and conservative alternatives for Class II malocclusion treatment. However, the literature is still controversial regarding the effects of using skeletal anchorage in intraoral distalizers with different designs. The aim of this study is to compare dentoskeletal and soft-tissue changes of Class II malocclusion patients treated with three types of First Class (FC) distalizers. MATERIALS/METHODS: The sample of this prospective clinical trial included 30 consecutive patients divided into three groups: G1-FC conventionally anchored; G2-FC skeletally anchored Type 1; G3-FC skeletally anchored Type 2. Each group consisted of 10 patients. Lateral cephalograms were analyzed in two stages: at pre-treatment (T0) and after distalization (T1). The radiographs were digitized and analyzed using the software Dolphin Imaging 11.5. Comparisons of treatment changes between groups (T1-T0) were performed using one-way analysis of variance (ANOVA), followed by the Tukey test. RESULTS: Patients treated with the conventionally anchored FC showed significantly greater incisors protrusion and labial inclination, second premolars mesial inclination and mesialization than the FCs skeletally anchored. No differences were observed regarding the amount of molar distalization and molar angulation between groups. LIMITATIONS: It can be considered that the limitation of this study lies in its non-randomized design. CONCLUSIONS/IMPLICATIONS: First Class distalizers with conventional and skeletal anchorage are effective alternatives for Class II molar distalization. Distalization associated with indirect skeletal anchorage reduce the undesirable effects observed in the incisors and premolars during distalization when compared to distalization conventionally anchored.

Finite element analysis of two skeletally anchored maxillary molar distalisation methods.

OBJECTIVE: To compare two methods of maxillary molar distalisation with skeletal anchorage using finite element analysis (FEA). METHODS: Two digitised models were created: the miniscrew-anchored distaliser, which consisted of a distalisation method anchored in a buccal miniscrew between the first molar and second premolar (Model 1), and the miniscrew-anchored palatal appliance, which consisted of a distalisation method anchored in a miniscrew on the anterior region of the palate (Model 2). FEA was used to simulate both methods, assessing teeth displacements and stress concentration. RESULTS: The miniscrew-anchored distaliser showed greater buccal than distal displacement of the first molar, while the opposite was observed in the miniscrew-anchored palatal appliance. The second molar responded similarly in the transverse and anteroposterior perspectives with both appliances. Greater displacements were observed at crown level than in apical regions. Greater stress concentration was observed at the buccal and cervical regions of the crown in the miniscrew-anchored distaliser and the palatal and cervical regions in the palatal appliance. The stress progressively spread in the buccal side of the alveolar bone for the miniscrew-anchored distaliser and in the palatal root and alveolar bone for the palatal appliance. CONCLUSION: FEA assumes that both appliances would promote maxillary molar distalisation. A skeletally anchored palatal distalisation force seems to provide a greater molar bodily movement with less undesirable effects. Greater stress is expected at the crown and cervical regions during distalisation, and the stress concentration in the roots and alveolar bone depends directly on the region the force was applied.

Treatment stability with bonded versus vacuum-formed retainers: a systematic review of randomized clinical trials.

BACKGROUND: In orthodontics, the retention phase can be considered challenging and unpredictable. Therefore, evidence obtained from different retention protocols is important to facilitate clinical decision-making. OBJECTIVES: This systematic review aimed to compare the clinical effectiveness of bonded versus vacuum-formed retainers (VFRs) regarding their capacity to maintain treatment stability, periodontal effects, and failure rates. SEARCH METHODS AND ELIGIBILITY CRITERIA: Ten databases comprising published and unpublished literature were systematically searched up to August 2021. Randomized clinical trials (RCTs) comparing both retainers were included. DATA COLLECTION AND ANALYSIS: The risk of bias (RoB) evaluation was performed with the Cochrane Collaboration RoB Tool 2.0. All steps of the screening phase and RoB assessment were performed independently by two reviewers. The Grade of Recommendations, Assessment, Development, and Evaluation (GRADE) was used to evaluate the certainty of the evidence. RESULTS: Initial database search yielded 923 studies. After duplicates removal and full-text assessment, five RCTs remained. Overall, the studies presented Low RoB, except one study judged with 'Some concerns'. Based on the included studies, on a short-term (3-6 months) and long-term (4 years) basis, bonded retainers (BRs) were more effective to maintain treatment stability than VFRs in the lower arch. However, from 12 to 24 months both retainers presented the same efficacy. In the upper arch, the retainers were equally effective. BRs were associated with greater plaque and calculus accumulation than VFRs after 12 months. The retainers' failure rates were similar in the upper arch on the first year of retention; however, after 2 years VFRs showed significantly greater failure rates. Contrarily, BRs presented greater failure rates in the lower arch than VFRs. LIMITATIONS: The findings of the included studies may be influenced by different factors related to the unpredictability of relapse. CONCLUSIONS: Most of the evidence generated in this systematic review derived from a moderate level of certainty. In the lower arch, BRs are more effective than VFRs to maintain treatment stability in the initial 6 months of retention and in the long term. In the upper arch, both retention protocols are equally effective. REGISTRATION: Regist0ration number: PROSPERO CRD42020199392. FUNDING: Coordination for the Improvement of Higher Educational Personnel (CAPES, Process code-001).

Mesioangulation of mandibular second molars: A case report.

This case report describes a simple alternative for treatment of mesioangulation of mandibular second molars. An 11-year-old girl was diagnosed with unilateral posterior crossbite, moderate incisor crowding and mesioangulation of the right mandibular second molar. The ectopic second molar was uprighted using a modified lingual arch with a distal hook and elastic chains. Orthodontic traction began after appliance installation and was activated once per month using 120 g of force. After six months, the right mandibular second molar was in an upright position. Orthodontic treatment continued with teeth levelling and alignment until acceptable occlusal and aesthetic results were achieved. Adequate stability was observed one year after debonding. The modified mandibular lingual arch with a distal hook is a simple and effective alternative to manage mesioangulation of mandibular second molars with minimum adverse effects and stable outcomes.

Effectiveness of lip repositioning surgeries in the treatment of excessive gingival display: A systematic review and meta-analysis.

To synthesize the available evidence regarding lip repositioning surgery (LRS) and quantify the short- and long-term reduction in excessive gingival display (EGD) with the procedure. Additionally, evaluate the effect of myotomy on the results. Seven electronic databases were searched up to May 2020 by two independent reviewers. Studies evaluating the exclusive use of LRS to treat EGD were included. After risk of bias assessment, the data were quantitatively evaluated with random-effects meta-analysis. The initial database search yielded 368 studies, of which 16 were selected for full-text review. Finally, eight studies were included. The random effects model exhibited an EGD reduction of 2.87 mm (95% CI: 1.91-3.82) after 3 months of LRS. These results decreased after 6 months (2.71 mm; 95% CI: 1.95-3.47) and 12 months (2.10 mm; 95% CI: 1.48-2.72). Meta-analysis comparing the performance of myotomy showed greater EGD reduction at 6 months than without myotomy (P < 0.02). LRS is an effective approach for treating EGD, and it has satisfactory results up to 6 months. After this period, the effectiveness appears to progressively decrease over time indicating substantial relapse at 12 months. Myotomy seems a suitable alternative to increase the stability of LRS. Lip repositioning surgery is an effective procedure to improve smile esthetics in the short-term (up to 6 months). After this period, the efficacy of LRS seems to decrease progressively, and an approximately 25% relapse may be expected after 12 months. Clinicians should combine the procedure with other approaches, such as plastic periodontal surgeries, restorative procedures, or botulin toxin injections for more predictable and stable outcomes.

Dental arch changes after open bite treatment with spurs associated with posterior build-ups in the mixed dentition: A randomized clinical trial.

INTRODUCTION: This single-center, 2-arm, parallel-group randomized clinical trial aimed to compare the dimensional dental arch changes after anterior open bite (AOB) treatment with bonded spurs associated with posterior build-ups vs bonded spurs alone. METHODS: Patients aged between 7 and 11 years with AOB were recruited at a university clinic and randomly allocated into 2 groups. The experimental group was treated with bonded spurs associated with posterior build-ups (SBU) and the comparison group with bonded spurs alone (S). Digital dental models were obtained at pretreatment and after 12 months of treatment. The overbite change was the primary outcome. The randomization list was obtained at the Web site www.randomization.com. Allocation concealment involved sequentially numbered, sealed, and opaque envelopes. The outcomes' assessment was blinded. Analysis of covariance was used for intergroup comparisons (P <0.05). Mean difference (MD) and 95% confidence interval (CI) were obtained. RESULTS: Twenty-four patients (mean age, 8.22 ± 1.06 years; 7 males and 17 females) were included in the SBU group, and 25 patients (mean age, 8.30 ± 0.99 years; 11 males and 14 females) were included in the comparison group. After a 12-month follow-up, the overbite increased approximately 4 mm in both groups (MD, -0.11 mm; 95% CI, -1.03 to 0.80). Means of anterior dentoalveolar vertical development ranged from 2.24 mm (S group) to 2.49 mm (SBU group) and from 1.31 mm (SBU group) to 1.55 mm (S group) for the maxilla (MD, -0.24 mm; 95% CI, -0.91 to 0.44) and mandible (MD, 0.29 mm; 95% CI, -0.39 to 0.96), respectively. The maxillary intermolar distance decreased in the SBU group and increased in the S group (MD, -0.48 mm; 95% CI, -0.92 to -0.03). The mandibular intermolar distance increased in the SBU group and decreased in the comparison group (MD, 0.26 mm; 95% CI, 0.004-0.52). Plaque accumulation around the spurs was observed in some patients. CONCLUSIONS: Both protocols demonstrated similar improvements in the AOB with similar effects on the dental arches. The SBU group showed a slight decrease in the maxillary intermolar distance and a slight increase in the mandibular intermolar distance, whereas opposite changes were observed for the S group. REGISTRATION: This trial was registered at Clinicaltrials.gov (Identifier NCT03702881). PROTOCOL: The study protocol was not published. FUNDING: This work was supported by the São Paulo Research Foundation (FAPESP) grants nos. 2017/06440-3, 2018/05238-9, and 2018/24003-2; and financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil (CAPES), Finance Code 001.

Class II malocclusion treatment with a customized dual force distalizer.

Intraoral distalizers associated with skeletal anchorage provide the major benefit of promoting molar distalization with minimum anchorage loss and patient cooperation. This case report presents the treatment of a 17-year-old female with Class II Division 2 malocclusion, maxillary dentoalveolar protrusion, mild mandibular retrusion, increased overjet, deepbite, and lip incompetence. The treatment plan involved initial maxillary molar distalization with a customized version of the skeletally anchored dual force distalizer (DFD). The customized DFD used smaller mini-implants and included a fixed anterior biteplane. The device applied simultaneous forces from the buccal and palatal sides directly to the molars using nickel-titanium coil springs and allowed orthodontic mechanics in the mandibular teeth. An overcorrected Class I molar relationship was obtained after 6 months. After the distalization phase, retraction mechanics began with retraction loops and using a modified transpalatal bar reinforced with the mini-implants as anchorage. Moreover, the finishing phase was performed with multiloop edgewise archwires and intermaxillary elastics to enable an individualized control of each tooth. Total treatment time comprised 2 years 4 months, and significant improvements regarding the facial and occlusal perspectives were noticed. Similarly, these favorable changes remained stable during the 2-year follow-up period. The customized version of the skeletally anchored DFD followed by fixed appliances showed effectiveness and stability in Class II malocclusion treatment.

Evaluation of root resorption following orthodontic intrusion: a systematic review and meta-analysis.

BACKGROUND/OBJECTIVE: To quantify the expected amount of orthodontically induced root resorption (OIRR) after orthodontic intrusion and assess the treatment-related factors. SEARCH METHODS AND ELIGIBILITY CRITERIA: Six electronic databases and partial grey literature were searched without limitations regarding language or publication year until April 2020. Randomized clinical trials and non-randomized prospective and retrospective studies evaluating root resorption after orthodontic intrusion were included. DATA COLLECTION AND ANALYSIS: Risk of bias (RoB) assessment was performed with the Cochrane Collaboration's RoB Tool 2.0 and ROBINS-I tool for the randomized and non-randomized studies, respectively. The data were combined into two random-effects meta-analyses estimating OIRR following orthodontic intrusion. One evaluated OIRR in the anterior region, while the other assessed OIRR in the posterior region. Sub-group analyses regarding the type of mechanics applied, duration of intrusion, amount of force, and sensitivity analysis of the study design and imaging examinations were also performed. The certainty of the evidence was assessed through the Grade of Recommendation, Assessment, Development, and Evaluation (GRADE) approach. RESULTS: The qualitative analysis included 14 studies; however, the meta-analysis was performed with 7 records. The random-effects model assumes that 0.72 mm [95% confidence interval (CI): 0.16 to 1.28] and 0.41 mm (95% CI: -0.24 to 1.07) of OIRR should be expected in the incisors and the molars, respectively. Sub-group analyses showed that the assessed treatment-related factors presented minimum impact in OIRR after orthodontic intrusion. The GRADE resulted in moderate and low certainty regarding the meta-analysis. LIMITATIONS: The major limitation of the present meta-analysis is that OIRR can be affected by several factors, some of which are assessed in this review. CONCLUSIONS: Orthodontic intrusion, evaluated as an isolated mechanic, caused less than 1 mm of OIRR, which is within the acceptable limits for clinical implication. Treatment-related factors did not show a significant influence on OIRR. REGISTRATION: This review was registered in PROSPERO, protocol number CRD42018098495.

Time of maxillary molar distalization with non-compliance intraoral distalizing appliances: a meta-analysis.

BACKGROUND/OBJECTIVE: To assess the mean maxillary molar distalization time with non-compliance intraoral distalizing appliances. SEARCH METHODS AND SELECTION CRITERIA: Database search included PubMed, Web of Science, Scopus, The Cochrane Library, Lilacs, and a partial grey literature through Google Scholar and OpenGrey. The search was performed until May 2017 and updated on February 2019, without limitations regarding publication year or language. Controlled clinical trials (randomized and non-randomized prospective studies) reporting duration of maxillary molar distalization of Class II patients treated with intraoral distalizers were included. DATA COLLECTION AND ANALYSIS: For the trials' quality assessment, the Cochrane Risk of Bias tool and the Cochrane Collaboration's ROBINS-I tool were used for the randomized controlled trials and non-randomized prospective studies, respectively. Database research, risk of bias (RoB) assessment, and extraction of data were performed by two independent investigators, with inclusion of a third reviewer, if disagreements emerged. Data was combined through a random-effects meta-analysis. Subgroup analyses regarding side of force application, type of anchorage, amount of molar distalization, and sensitivity analysis comparing study designs were also performed. Quality of evidence was assessed using the GRADE and SORT approaches. RESULTS: Nine studies were included in the qualitative analysis; however, a meta-analysis was performed with only four studies, due to the presence of high RoB in the other studies. The random-effects meta-analysis assumes that the mean distalization time with distalizers is 8.34 months (95% confidence interval: 6.10, 10.58). Another meta-analysis was performed to evaluate the relationship between distalization time and the type of anchorage (conventional or skeletal), resulting in no significant difference. Both meta-analyses presented low-quality evidence. LIMITATIONS: The major limitation of this meta-analysis is the fact that distalization time can be affected by a great range of factors. CONCLUSIONS AND IMPLICATIONS: Correction of a half-to-full cusp Class II molar relationship with intraoral distalizers can be achieved in 8.34 months, and this distalization time may not be affected by the kind of anchorage used. REGISTRATION: The protocol for this systematic review was based on the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 and was registered at PROSPERO database (http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017068737). This systematic review is reported according to the PRISMA statement.