Soft and Hard Tissue Changes Following Treatment of Class II Division 1 Malocclusion with Twin-Block and Myofunctional Appliance: A Pilot Study

Abstract

ABSTRACT Background Many cases of Class II deformities have been reported to be treated with prefabricated appliances. The aim of this study was to distinguish the clinical effect of traditional custom-made appliances and prefabricated appliances in the treatment of Class II division 1 malocclusion. Therefore, soft and hard tissue changes following treatment of Class II division 1 malocclusion using the twin-block (TB) appliance was compared to that using the Myofunctional Research Company (MRC) appliance (K1 + K2) combined with oral myofunctional treatment (OMT) (MRC + OMT). Methods The study included 22 children (6 boys and 16 girls aged 9–11 years) with Class II division 1 malocclusion along with mandibular retrognathism with a 5–12 mm overjet, basic normal maxillary status, and stage 2 or 3 cervical vertebral maturation (CVM). Participants were randomly assigned into two groups, the TB group and the MRC + OMT group for 12 months. Standardized lateral cephalograms were used to assess skeletal, dental, and soft tissue changes from pre- to post-treatment. Independent t-tests were used to compare the initial and final cephalometric status and tissue changes between the groups. Results The TB and MRC + OMT groups resulted in different degrees of lateral changes; however, improvements of skeletal and soft tissue indices were significantly greater in the TB group than in the MRC + OMT group. Conclusion TB was more effective than MRC + OMT in treating children aged 9–11 years with Class II division 1 malocclusion. However, further research using custom-made appliances with OMT is recommended, and further investigations are needed to confirm these findings.