Dentoskeletal Effects of the Modified Tandem Appliance vs the Facemask Appliance in the Treatment of Skeletal Class III Malocclusion: A Single-center, Randomized Controlled Trial.

Aims: The aim of this randomized controlled trial was to compare the skeletal and dentoalveolar effects of the modified tandem appliance (MTA) vs the facemask (FM) with rapid maxillary expansion.

Materials And Methods: Thirty-two patients, aged 7 to 9 years were recruited. Eligibility criteria included skeletal class III malocclusion that resulted from the retrusion of the maxilla. Randomization was accomplished to divide the sample into two equal groups to be treated with either MTA or FM. Lateral cephalometric radiographs were obtained before treatment and after 2 mm positive overjet was achieved. Intragroup comparisons were performed using paired-sample t-test, and intergroup comparisons were performed using two-sample t-test at the p ≤ 0.05 level.

Results: Thirty-two patients (16 in each group) were available for statistical analysis. The pretreatment variables of both groups were similar. Both treatment therapies showed similar significant increase in the SNA and ANB angles, accompanied by slight decrease in the SNB angle. The increase in the SN:GoMe angle, Bjork's sum, and the overjet were significantly greater in the FM group. The forward movement of upper dentition was similar in both groups. Although the lower incisors retrusion was significantly greater in the FM group than in the MTA group, the uprighting of the lower molars was significantly greater in the MTA group.

Conclusion: Both appliances showed similar effects apart from less clockwise rotation of the mandible, less retrusion of the lower incisors, and greater uprighting of the lower molars in the MTA group.

Clinical Significance: Both the MTA and the FM groups are effective in treating class III malocclusion. The MTA group is more efficient in controlling the clockwise rotation and gaining some space in the lower arch.