Effectiveness of prefabricated myofunctional appliances in the treatment of Class II division 1 malocclusion: a systematic review.

BACKGROUND: Prefabricated myofunctional appliances (PMAs) are widely advocated for correcting Class II division I malocclusion. However, their effectiveness is associated with a high amount of uncertainty within contemporary literature. OBJECTIVES: The aim of this review was to systematically examine the available literature regarding the effectiveness of PMAs in treating Class II division 1 malocclusion in children and adolescents. SEARCH METHODS: Comprehensive unrestricted electronic searches in multiple databases as well as manual searches were conducted up to August 2018. SELECTION CRITERIA: Randomized controlled trials (RCTs) and non-randomized studies (NRS) matching the eligibility criteria. DATA COLLECTION AND ANALYSIS: Two independent review authors were directly involved in study selection, data extraction, and bias assessment. The Cochrane risk of bias tool and the ROBINS-I tool were used for assessing the risk of bias. Quantitative pooling of the data was undertaken with a random-effects model with its 95% confidence interval (CI). RESULTS: Three RCTs comparing PMAs to activators and three NRS comparing PMAs to untreated controls met the inclusion criteria. On a short-term basis, exploratory quantitative synthesis indicated that the activators were more effective than the PMAs in correcting overjet with a mean difference of (1.1 mm; 95% CI: 0.44 to 1.77). On a long-term basis, there were no significant differences between the two appliances. Qualitative synthesis indicated less favorable soft tissue changes as well as patient experiences and compliance with the PMAs when compared to the activators. However, PMAs were associated with reduced costs compared to customized activators and modest changes when compared to untreated controls. CONCLUSIONS: On a short-term basis, low quality of evidence suggests that PMAs were generally less effective than the activators in treating Class II division 1 malocclusion. The main advantage of PMAs seems to be their reduced costs. These results should be viewed with caution, as a definitive need for high-quality long-term research into this area is required. REGISTRATION: PROSPERO (CRD42018108564).

A cost-minimization analysis of large overjet reduction with two removable functional appliances based on a randomized controlled trial.

Objective: The purpose of this study was to assess and relate the societal costs of reducing large overjet with a prefabricated functional appliance (PFA), or a slightly modified Andresen activator (AA), using a cost-minimization analysis (CMA). Design, settings, and participants: A multicentre, prospective, randomized clinical trial was conducted with patients from 12 general dental practices. Ninety-seven patients with an Angle Class II, division 1 malocclusion, and an overjet of ≥6 mm were randomly allocated by lottery to treatment with either a PFA or an AA. The PFA and AA groups consisted of 57 and 40 subjects, respectively. Blinding was not performed. Duration of treatment, number of scheduled/unscheduled appointments, and retreatment were registered. Direct and indirect costs were analysed with reference to intention-to-treat (ITT), successful (S), and unsuccessful (US) outcomes. Societal costs were described as the total of direct and indirect costs, not including retreatments. Interventions: Treatment with a PFA or an AA. Results: The direct and societal costs were significantly lower for the PFA than for the AA group. The number of visits was lower in the PFA group, when ITT was considered, and for the US cases as well. No difference in retreatment rate could be seen between the groups. Limitations: Costs depend on local factors and thus should not be generalized to other settings. Harms: No harms were detected during the study. Conclusion: The success rate of the both appliances was low. However, the PFA was the preferred approach for reduction of a large overjet in mixed dentition, since it minimized costs and there were no difference in clinical outcomes between PFA and AA. Registration: This trial was registered at 'FoU i Sverige' (http://www.fou.nu/is/sverige), registration number: 97131. Protocol: The protocol was not published before trial commencement.

Discomfort, expectations, and experiences during treatment of large overjet with Andresen Activator or Prefabricated Functional Appliance: a questionnaire survey.

BACKGROUND: The purpose of this study was to investigate the amount of functional and social discomfort experienced after 1 and 6 months of appliance wear, comparing a slightly modified Andresen Activator (AA) and a Prefabricated Functional Appliance (PFA). METHODS: Ninety-seven patients randomly selected by lottery in an AA (40 subjects), and a PFA (57 subjects) group, with an Angle Class II, Division 1 malocclusion, were eligible for the study. One month and 6 months after start of treatment, a questionnaire, addressing discomfort, perception of treatment need and outcome, was used. RESULTS: The response rate was 69% after 1 month, and 45% after 6 months. The most common discomfort reported was the 'appliance falling out during sleep' followed by 'difficulties in remembering it'. The only difference was for pain, which was experienced more extensively in the AA group after 1 month of treatment. The dentist appeared to have the greatest impact on the decision to initiate treatment. Teasing, because of appearance, occurred in 13% of the cases. CONCLUSIONS: No difference could be seen between groups for the experience of functional or social discomfort after 6 months of appliance use. Adequate time should be allowed for clarifying treatment difficulties, using treatment need as motivation. PRACTICAL IMPLICATIONS: The PFA eliminates the need for taking impressions. Furthermore, it can be economically advantageous to both patients and clinicians.

Treatment of large overjet in Angle Class II: division 1 malocclusion with Andresen activators versus prefabricated functional appliances-a multicenter, randomized, controlled trial.

OBJECTIVES: The purpose of this study was to compare the clinical effectiveness in reducing large overjet between a prefabricated functional appliance (PFA) and a slightly modified Andresen activator (AA). SETTING AND SAMPLE POPULATION: Public Dental Service, Gothenburg, Sweden. PARTICIPANTS, STUDY DESIGN, AND METHODS: A multicentre, prospective randomized clinical trial was conducted with patients from 12 general dental practices. One hundred and five patients with an Angle Class II, division 1 malocclusion and an overjet of ≥6mm were eligible for the study. Eight patients were excluded due to various reasons and the sample consisted thus of 97 subjects (44 girls, 53 boys) with a mean age of 10.3 years. The study was designed as intention to treat and the patients were randomly allocated by lottery to treatment with either a PFA or an AA. The PFA and AA group consisted of 57 subjects (28 girls, 29 boys) and 40 subjects (16 girls, 24 boys), respectively. Overjet, overbite, lip seal, and sagittal molar relationship were recorded before, at the end of treatment and 1-year post-treatment. Blinding was not performed. The endpoint of treatment was set to overjet ≤3mm and after this a 6 months retention period followed. RESULTS: No significant difference was found in overjet, overbite, sagittal relation, and lip seal between the two groups for the total observation period. The treatment of 40 (70 per cent) patients with PFA and 21 (53 per cent) with AA were considered unsuccessful mainly due to poor compliance. LIMITATIONS: No cephalometric records were taken as only patient-centred clinical outcome were used as an indicator for treatment success. The criteria of reduction of overjet to as low as 3mm could have affected the success rate. CONCLUSION: No difference in effectiveness could be shown between PFAs and AAs in correcting overjet, overbite, sagittal molar relation, and lip seal. The success rate in treatment with both appliances is, however, low. REGISTRATION: This trial was registered in "FoU i Sverige" (http://www.fou.nu/is/sverige), registration number: 97131. PROTOCOL: The protocol was not published before trial commencement.

Validity of digital analysis versus manual analysis on orthodontic casts.

BACKGROUND: As artificial intelligence within digital processes continues to advance and replace conventional manual workflows, it is crucial that digital data are consistent with analog data. The aim was to evaluate the validity and time efficiency of digital cast analysis on digital models in comparison with the manual, gold standard, cast analysis on plaster models. METHODS: Cast analysis was performed on 30 patients in three various methods: manually measured variables on plaster models (MP), manually measured variables on digital three-dimensional models (MD), and automatically measured variables on digital three-dimensional models (AD) on digital models. Digital cast analysis was performed in CS Model+. Analyses included metrical and categorical variables and the required work time. Measurements in MD and AD were validated to MP. Validity of the metrical variables was analyzed with Bland-Altman, Dahlberg's formula, and paired sample t test. Categorical variables were validated by Cohen's Kappa. Work time was analyzed with Wilcoxon signed-rank test. RESULTS: Metrical variables had measurement errors ranging 0.4 to 1.4 mm between MP-MD, and 0.6 to 3.2 mm between MP-AD. Observations of categorical variables had a moderate to strong (0.65 to 0.9) level of agreement between MP-MD, and a weak to moderate (0.4 to 0.68) level of agreement between MP-AD. Data for dental stage, vertical, and transversal relation was not provided in AD. Cast analysis was performed quicker digitally, P ≤ 0.05. CONCLUSIONS: Digital cast analysis is consistent with manual cast analysis for metrical variables. Analyses of categorical variables show a weak level of agreement with automatic digital analysis, such as space conditions and midline assessments. Digital cast analysis optimizes time compared with manual cast analysis, with automatic analysis being the fastest.

Survey on retention procedures and use of thermoplastic retainers among orthodontists in Norway, Sweden, and Denmark.

BACKGROUND: Orthodontic retention is the most important factor after successful orthodontic treatment. The use of thermoplastic retainers has increased in recent years, but information is lacking about the product materials and orthodontists' awareness of the products they use. The aim of this survey was to map the retention protocols among Scandinavian orthodontists, particularly their use of thermoplastic retainers. Furthermore, the aim was to investigate their knowledge of thermoplastic materials and record any possible adverse effects. METHODS: An online questionnaire was prepared, and 667 orthodontists in Norway, Sweden, and Denmark were invited to take the survey. The survey was sent to all members of the national orthodontic associations using Nettskjema in Norway and Microsoft Forms in Sweden and Denmark. Data were collected anonymously and analyzed using chi-square and correlation coefficients. RESULTS: Of the 667 orthodontists, 432 (64%) responded (59% female). The most common retention protocol (51%) was fixed retainer in both maxilla and mandible and thermoplastic retainer in the maxilla. Two-thirds of the orthodontists were unaware of the thermoplastic material used, and 58% did not acquire knowledge of the materials. Only 1% of the respondents had registered adverse reactions to thermoplastic retainers, and none were aware of the type of material that was used. CONCLUSIONS: Scandinavian orthodontists use similar retention protocols, with the most common being fixed retainer in the mandible and dual retention, fixed, and thermoplastic retainer in the maxilla. Orthodontists' knowledge about thermoplastic materials was insufficient, but adverse effects related to thermoplastic retainer use were rare.

Early plaque formation on PTFE membranes with expanded or dense surface structures applied in the oral cavity of human volunteers.

OBJECTIVES: This clinical randomized study aimed to evaluate the early plaque formation on nonresorbable polytetrafluoroethylene (PTFE) membranes having either a dense (d-PTFE) or an expanded (e-PTFE) microstructure and exposed to the oral cavity. MATERIAL AND METHODS: Twelve individuals were enrolled in this study. In a split-mouth design, five test membranes (e-PTFE) with a dual-layer configuration and five control membranes (d-PTFE) were bonded on the buccal surfaces of posterior teeth of each subject. All study subjects refrained from toothbrushing during the study period. Specimens were detached from the teeth at 4 and 24 hr and subjected to viability counting, confocal microscopy, and scanning electron microscopy. Plaque samples were harvested from neighboring teeth at baseline, 4, and 24 hr, as control. Wilcoxon signed rank test was applied. RESULTS: No bond failure of the membranes was reported. Between the early and late time points, viable bacterial counts increased on all membranes, with no difference between the test and control. The number of Staphylococcus spp. decreased on the tooth surfaces and increased on both membranes overtime, with a significant difference compared to teeth. The total biomass and average biofilm thickness of live and dead cells were significantly greater at the d-PTFE barriers after 4 hr. CONCLUSION: This study demonstrated that the e-PTFE membrane was associated with a lesser degree of biofilm accumulation during the initial exposure compared to the d-PTFE membrane. The present experimental setup provides a valuable toolbox to study the in vivo behavior of different membranes used in guided bone regeneration (GBR).