Dentofacial effects of skeletal anchored treatment modalities for the correction of maxillary retrognathia.Am J Orthod Dentofacial Orthop. 2014 Jan; 145(1):41-54.AJ
The aim of this clinical study was to investigate the skeletal, dentoalveolar, and soft-tissue effects of 2 skeletal anchorage rationales for Class III treatment compared with an untreated Class III control group.
Fifty-one subjects who were in the prepubertal or pubertal growth period were included in the study. In group 1 (n = 17), facemasks were applied from miniplates placed in the lateral nasal walls of the maxilla, and intermaxillary Class III elastics were applied from symphyseal miniplates to a bonded appliance on the maxilla in group 2 (n = 17). These skeletal anchored groups were compared with an untreated control group (n = 17). Lateral cephalometric radiographs were obtained at the beginning and the end of the observation periods in all groups and analyzed according to the structural superimposition method. Differences between the groups were assessed with the Wilcoxon signed rank test or the paired-samples t test.
The treatment periods were 7.4 and 7.6 months in groups 1 and 2, respectively, and the untreated control group was observed for 7.5 months. The maxilla moved forward by 3.11 mm in group 1 and by 3.82 mm in group 2. The counterclockwise rotation of the maxilla was significantly less in group 1 compared with group 2 (P <0.01). The mandible showed clockwise rotation and was positioned downward and backward in the treatment groups, and it was significantly greater in group 2 compared with group 1 (P <0.01). Changes in the maxillary incisor measurements were negligible in group 1 compared with group 2. A significant amount of mandibular incisor retroclination was seen in group 1, and a significant proclination was seen in group 2. The maxillomandibular relationships and the soft-tissue profiles were improved remarkably in both treatment groups.
The protocols of miniplates with facemasks and miniplates with Class III elastics offer valid alternatives to conventional methods in severe skeletal Class III patients. However, the 2 maxillary protraction protocols demonstrated significant skeletal and dentoalveolar effects. The miniplate with facemask protocol is preferred for patients with severe maxillary retrusion and a high-angle vertical pattern, whereas in patients with a decreased or normal vertical pattern and retroclined mandibular incisors, miniplates with Class III elastics can be the intraoral treatment option. Therefore, the exact indication of the procedure should be considered carefully.