Comparative effects of the Mandibular Protraction Appliance in adolescents and adults

Age-related alveolar bone maladaptation in adult orthodontics: finding new ways out

Compared with teenage patients, adult patients generally show a slower rate of tooth movement and more pronounced alveolar bone loss during orthodontic treatment, indicating the maladaptation of alveolar bone homeostasis under orthodontic force. However, this phenomenon is not well-elucidated to date, leading to increased treatment difficulties and unsatisfactory treatment outcomes in adult orthodontics. Aiming to provide a comprehensive knowledge and further inspire insightful understanding towards this issue, this review summarizes the current evidence and underlying mechanisms. The age-related abatements in mechanosensing and mechanotransduction in adult cells and periodontal tissue may contribute to retarded and unbalanced bone metabolism, thus hindering alveolar bone reconstruction during orthodontic treatment. To this end, periodontal surgery, physical and chemical cues are being developed to reactivate or rejuvenate the aging periodontium and restore the dynamic equilibrium of orthodontic-mediated alveolar bone metabolism. We anticipate that this review will present a general overview of the role that aging plays in orthodontic alveolar bone metabolism and shed new light on the prospective ways out of the impasse.

Stability of Class II malocclusion treatment with Class II elastics

INTRODUCTION

The objective of this study was to compare the long-term cephalometric stability after successful therapy of nonextraction Class II malocclusion with elastics and with headgear.

METHODS

The sample comprised 43 patients with Class II malocclusion and was divided into 2 groups. The elastic group (EG) consisted of 20 patients treated with fixed appliances associated with Class II elastics, and the headgear group (HG) consisted of 23 patients treated with fixed appliances and extraoral headgear. Pretreatment, posttreatment, and long-term posttreatment lateral radiographs were evaluated; t tests were used to compare the long-term posttreatment changes between the groups.

RESULTS

The groups were matched regarding initial age, time of long-term posttreatment evaluation, initial malocclusion severity, quality of treatment result, and all pretreatment cephalometric variables. Intergroup comparisons of long-term posttreatment changes showed that the HG group presented significantly greater mandibular protrusion, occlusal plane angle decrease, and maxillary molar mesialization. However, long-term posttreatment stability was similar in overjet, overbite, and molar relationships.

CONCLUSIONS

Nonextraction Class II malocclusion treatment with elastics or extraoral headgear have similar long-term posttreatment stability.

Assessment of the relationship between fractal analysis of mandibular bone and orthodontic treatment duration : A retrospective study

PURPOSE

This retrospective study aimed to determine whether a correlation exists between the fractal dimension value and overall orthodontic treatment duration in children and young adults.

METHODS

The study included a total of 643 patients (age: 10-25 years) who received orthodontic treatment between January 2015 and March 2020. Patient records and pretreatment panoramic radiographs were evaluated. The regions of interest selected for calculating fractal dimension were the bilateral mental foramen regions of the mandible. Fractal dimension was set in relation to orthodontic treatment duration using a linear regression model which was also adjusted for potential confounding variables. Total treatment duration was the outcome variable of interest used as a continuous variable. The predictor variables of interest included age, gender, type of dental and skeletal malocclusion, vertical growth pattern, extraction type, and fractal dimension.

RESULTS

The mean age, treatment duration, and fractal dimension were 14.56 years, 27.01 months, and 1.23 mm, respectively. Multiple linear regression analysis showed that the fractal dimension had a significant influence on overall treatment duration (P < 0.001). From the other variables, Angle class II malocclusion significantly influenced treatment duration (P < 0.01), age showed a significant negative correlation with treatment duration (P < 0.01), and treatment duration significantly increased for patients with tooth extractions (P < 0.001).

CONCLUSION

There was a negative correlation between fractal dimensions at the mandibular mental region and total orthodontic treatment duration. Fractal dimension analysis may help to understand physiologic features of alveolar bone and predict orthodontic tooth movement.

Duration of orthodontic treatment with fixed appliances in adolescents and adults: a systematic review with meta-analysis

OBJECTIVES

Adults with fixed orthodontic appliances are increasing nowadays. Compared with adolescents, adults present biological differences that might influence treatment duration. Therefore, the aim of the study was to compare duration of treatment with fixed appliances between adults and adolescents.

MATERIALS AND METHODS

Eight databases were searched up to September 2019 for randomized and non-randomized clinical studies comparing treatment duration with fixed appliances in adolescents and adult patients. After duplicate study selection, data extraction, and risk of bias assessment with the Cochrane ROBINS-I tool, random effects meta-analyses of mean differences (MD) and their 95% confidence intervals (CIs) were performed, followed by assessment of the quality of evidence with GRADE.

RESULTS

A total of 11 unique studies (one prospective and 10 retrospective non-randomized) with 2969 adolescents and 1380 adult patients were finally included. Meta-analysis of 7 studies found no significant difference in the duration of comprehensive treatment with fixed appliances (MD = - 0.8 month; 95% CI = - 4.2 to 2.6 months; P = 0.65; I2 = 92%) between adults and adolescents. Similarly, both distalization of upper first molars with skeletal anchorage for class II correction and the retraction of canines into the premolar extraction spaces lasted similarly long among adults and adolescents. On the other hand, alignment of palatally displaced canines lasted considerably longer in adults compared to adolescents (1 study; MD = 3.8 months; 95% CI = 1.4 to 6.2 months; P = 0.002). The quality of evidence for the meta-analysis was low due to the inclusion of non-randomized studies with considerable risk of bias.

CONCLUSIONS

While existing evidence does not indicate a difference in the overall duration of treatment with fixed appliances between adults and adolescents, the alignment of palatally displaced canines lasted significantly longer in adults. However, our confidence in these estimates is low due to the risk of bias in the included studies.

TRIAL REGISTRATION

PROSPERO: ( CRD42019148169 ).

Mandibular propulsion appliance for adults with Class II malocclusion: a systematic review and meta-analysis

BACKGROUND

The effects of mandibular propulsion appliances in adults have some controversial results. While some authors claim that its use in non-growing patients could produce some dentoskeletal effects, other studies indicate that Class II correction occurs only through significant dental effects.

OBJECTIVE

To evaluate the effects in non-growing Class II patients with mandibular retrusion, promoted by the treatment with mandibular propulsion appliances and determine if they produce mandibular changes.

METHODS

The research was carried out in nine electronic databases and additional manual searches up to July 2019. Selection criteria were no restriction was placed on date and publication language. Randomized or non-randomized clinical trials with/without control were included. They must evaluated non-growing patients with Class II malocclusion, treated with mandibular propulsion appliances; outcomes were assessed before and after treatment.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent examiners in duplicate. The ROBINS-I tool was used to assess the methodological quality of the included studies.

RESULTS

Of the 2824 articles identified, 11 non-randomized clinical articles were selected for qualitative analysis and 8 for quantitative analysis. SNB (0.87°, CI 95% 0.08, 1.66), ANB (-0.82°, CI 95% -1.24 to 0.40) and Pg/OLp [2.3 to 1.2 mm (P < 0.001)] presented smallest but significant mandibular changes with some differences regarding the used appliance. The Herbst appliance showed the largest mandibular changes followed by the SUS appliance when evaluated through Ar-Pg. SNA showed non-significant changes. Overbite (-2.85. CI 95% -3.06, -2.64), Overjet (-5.00.CI 95% -5.45, -4.55) showed significant changes in all devices. Class II correction occurs through a significant labial movement of the mandibular incisors, some lingual inclination of the maxillary incisors and minor skeletal changes.

CONCLUSIONS

All mandibular propulsion appliances examined, showed efficiency in normalizing the Class II malocclusion in adult patients; however, changes were acquired mainly through dentoalveolar changes. Some minor mandibular forward changes was noted, mainly in patients treated with the Herbst appliance. Randomized clinical trials are needed to improve scientific evidence.

REGISTRATION

PROSPERO (code CRD42017067384).

Different approaches to the treatment of skeletal Class II malocclusion during growth: Bionator versus extraoral appliance

INTRODUCTION

Class II malocclusion, which has a significant incidence in the population, may compromise facial esthetics and the smile, as well as the masticatory and respiratory functions. Often associated with skeletal abnormalities, it severely affects and compromises quality of life. An accurate diagnosis is fundamental to prepare a treatment plan to correct dental and skeletal anomalies.

OBJECTIVES

This study discusses treatment alternatives to the correction of Class II division 1 and 2 malocclusion in growing patients, using a Bionator and an extraoral appliance.