LAUSR

Background Increased awareness on the role of oral functions in the aetiology of Class II deformities has led to the wide spread of myofunctional training appliances as easy and possibly effective treatment for children with Class II malocclusion but their efficacy is yet to be proven. Objectives To evaluate soft- and hard-tissue changes following 12 months of Class II division 1 treatment in growing patients with a conventional functional appliance (a modified Activator) versus a myofunctional Trainer system (T4K®). Setting and sample population Department of Orthodontics, Dental School. Participants, study design, and methods Sixty Class II division 1 children (8-12 years old) were recruited from primary schools and were distributed randomly into two equal groups. Randomization was based on a computer-generated sequence of random numbers. Data analysis included: the Activator group (28 patients, mean age = 10.6 ± 1.3 years); the T4K® group (26 patients, mean age = 10.3 ± 1.4 years). Skeletal, dentoalveolar, and soft tissues changes were assessed using standardized lateral cephalograms collected before and after 12 months of treatment. No blinding was applied in this trial. Results Improvement in the Class II skeletal and dentofacial characteristics were significantly greater in the Activator group when compared with the T4K® group. The improvement was evident in a significant decrease in the skeletal angle ANB with Activator (x¯ = -1.89 ± 1.12) compared to T4K® (x¯ = -0.9 ± 1.01) (P = 0.01), a significant greater increase in the facial convexity angle with Activator (x¯ = 2.61 ± 3.71) more than T4K® (x¯ = 0.2 ± 2.51) (P = 0.04), and a significant reduction in the overjet (x¯ = -3.0 ± 2.3 mm) compared to (x¯ = -1.5 ± 1.9 mm; P = 0.01) with Activator versus T4k®, respectively (P = 0.001). Limitations This study was a short-term study (12-month follow-up). Conclusions The results of the current study indicated that the Activator was more effective than the T4K® in treating Class II division 1 growing patients. Registration The trial was not registered in any major database of clinical trials. Protocol The protocol was not published before the commencement of the trial but can be given upon request.