Short-term effects of the orthodontic removable traction appliance in the treatment of skeletal Class III malocclusion: A randomized controlled trial

Abstract

Background: The orthodontic removable traction appliance (ORTA) was introduced as an intraoral removable appliance to treat Class III patients, but the pure treatment effects of ORTA have not been established yet.

Objectives: The aim of the study was to evaluate the skeletal, dental and soft tissue changes following the use of ORTA in treating Class III growing patients, and to compare these changes with those observed in an untreated control group (UCG).

Material and methods: Forty-two patients with Class III malocclusion (mean age: 9.04 ±0.84 years) were randomly allocated to either the intervention group (ORTA) or UCG with a 1:1 allocation ratio. The patients in the ORTA group were treated until a positive overjet was achieved, whereas those in UCG were observed for an average of 6 months. Lateral cephalograms were obtained before (T1) and at the end of the treatment or observation period (T2). Twenty-six variables were used to evaluate treatment changes. The paired and independent t tests were used to detect significant differences within and between the groups, respectively.

Results: Forty-two patients who met the inclusion criteria were included primarily. Two patients in UCG dropped out of the study. Therefore, 40 patients were included in the statistical analyses (ORTA: 21; UCG: 19). The orthodontic removable traction appliance was able to correct Class III malocclusion in a mean treatment time of 4.34 ±2.02 months. The maxilla moved forward by a mean of 1.31°, which was significantly greater than in the case of UCG (i.e., a mean difference of 1.02°). The mandible moved significantly backward in the ORTA group (the mean change in SNB: -1.85°) and significantly forward in UCG (the mean change in SNB: 0.97°), leaving the overall sagittal skeletal change significantly greater in the ORTA group as compared to UCG (the mean change in ANB: 3.81°) (p < 0.001).

Conclusions: In the short term, ORTA seemed to be an effective intraoral removable appliance in the treatment of growing Class III patients.

Keywords: angle Class III; malocclusion; removable orthodontic appliances.