Dentofacial and skeletal effects of two orthodontic maxillary protraction protocols: bone anchors versus facemask

Abstract

Background Maxillary retrognathia and/or mandibular prognathia are resulting in class III malocclusion. Regarding orthodontic class III malocclusion treatment, the literature reports several treatment approaches. This comparative clinical study investigated two maxillary protraction protocols including bone anchors and Delaire type facemask. Methods Cephalometric radiographs of n=31 patients were used for data acquisition. The patients were divided into two groups according to their treatment protocol: bone anchored protraction (n=12, 8 female, 4 male; mean age 11.00±1.76 years; average application: 13.50±5.87 months) and facemask protraction (n=19, 11 female, 8 male; mean age 6.74±1.15 years; average application: 9.95±4.17 months). The evaluation included established procedures for measurements of the maxilla, mandibula, incisor inclination and soft tissue. Statistics included Shapiro-Wilk- and T-Tests for the radiographs. The level of significance was set at p<0.05. Results The cephalometric analysis showed differences among the two groups. SNA angle showed significant improvements during protraction with bone anchors (2.30±1.18°) with increase in the Wits appraisal of 2.01±2.65 mm. SNA angle improved also during protraction with facemask (1.22±2.28°) with increase in the Wits appraisal of 1.85±4.09 mm. Proclination of maxillary incisors was larger in patients with facemask (3.35±6.18°) and ML-SN angle increased more (1.05±1.51°) than in patients with bone anchors. Loosening rate of bone anchors was 14.58%. Conclusions Both treatment protocols led to correction of a class III malocclusion. However, this study was obtained immediately after protraction treatment and longitudinal observations after growth spurt will be needed to verify the treatment effects over a longer period. The use of skeletal anchorage for maxillary protraction reduces unwanted side effects and increases skeletal effects needed for class III correction.