Retrospective 3-dimensional Evaluation of Skeletal and Dental Structures Following Treatment with Hybrid Hyrax-Mentonplate with Class III Elastics in Class III Patients with Vertical Growth Pattern: A Pilot Study

Objective: The aim of the present study is to evaluate the skeletal and dental changes three-dimensionally in patients with skeletal Class III malocclusion and vertical growth pattern treated with hybrid hyrax-mentonplate and Class III elastic combination. Materials and Methods: In this retrospective study, cone-beam computed tomography images of 6 patients (5 females and 1 male; Mean age: 11.9±0.9 years) who had undergone an orthopedic treatment with hybrid hyrax-mentonplate and Class III elastic combination were retrieved from the archive of … University, Department of Orthodontics. Initial and post-protraction skeletal and dental parameters were investigated by using 3D SLICER version 5.0.2 software (www.slicer.org). The Wilcoxon paired-sample test was used for comparing initial and post-protractional changes. Statistical significance was set at p<0.05. Results: Sagittal skeletal evaluation showed statistically significant increases of 2.31° in SNA, and 2.8° in ANB (p<0.05) with no significant change in SNB (p0.05). There were no significant changes in vertical skeletal parameters except significant decreases in FH-OP and SN-OP angles of 5.28° and 5.18°, respectively. In terms of dental changes, while a significant decrease was found in LI-OP angle (8.82°), significant increases in LI-MP angle and in overjet change were found (5.27°, 3.75 mm, respectively) (p<0.05). There were no significant changes in upper incisor parameters, UI-LI angle, and overbite (p0.05). Conclusion: With the use of hybrid hyrax-mentoplate and Class III elastic combination, orthopedic sagittal correction can be achieved in patients presenting high angle skeletal Class III without causing any changes in facial height, and the slope of mandibular and palatal planes.