Comparison between maxillary skeletal expander and hybrid hyrax facemask combination in treatment of growing patients with skeletal class III malocclusion: a randomized clinical trial

Abstract

IntroductionIt has been demonstrated that the use of skeletal anchoring devices for maxillary protraction is a potential method for treating growing patients with class III malocclusion caused by maxillary retrognathism. The aim was to compare the skeletal and dentoalveolar effects of maxillary skeletal expander and hybrid hyrax facemask combination in the treatment of developing skeletal class III malocclusion.Patients and methodsThe study comprised 30 developing class III participants randomly selected with maxillary retrognathism in the late mixed or early permanent dentition. In group 1 (n = 10) patients, the maxillary skeletal expander facemask technique was utilized. In group 2 (n = 10) patients, the hybrid hyrax facemask technique was utilized. Group 3 (n = 10) patients, a control with no treatment group. Analysis of pretreatment and posttreatment cephalometric radiographs was used to evaluate skeletal changes.ResultsThe treatment periods for groups 1 and 2 were 8 and 8.5 months, respectively, whereas the untreated control group was followed for 9 months. In comparison to the untreated control group, the maxilla shifted markedly forward in groups 1 and 2 (4.65 mm in group 1 and 3.72 mm in group 2); overjet was improved without proclination of the upper incisors. However, group 2 had more mandibular opening rotation than group 1.ConclusionThe two maxillary protraction protocols effectively corrected the significant maxillary deficiency in developing class III patients. However, vertical alterations were better controlled by the maxillary skeletal expander facemask combination (group 1), thus it can be used to treat developing class III patients with a hyperdivergent growth pattern.