Abstract
Objective: This study aimed to evaluate the long-term changes in the pharyngeal dimensions and hyoid bone position in Class II malocclusion patients treated with Herbst functional appliance.
Design: Retrospective cohort study.
Setting: Department of Orthodontics, Bauru Dental School, University of São Paulo – Brazil.
Methods: The sample comprised 15 skeletal Class II malocclusion patients (13.00 years old ± 1.21) treated with Herbst functional appliance and followed for a mean period of 10 years (10.73 years ± 3.67). Lateral headfilms were used to evaluate the pharyngeal dimensions and hyoid bone position, and the measurements were performed with Dolphin® Imaging 11.9. Intragroup comparison between the evaluation stages was performed with repeated measures ANOVA, followed by Tukey tests if necessary. Results were considered statistically significant at p<0.05.
Results: Regarding the pharyngeal cephalometric variables, only the lower airway space increased significantly in the treatment period, and all of them remained stable remained stable during follow-up period. The hyoid bone moved significantly forward and downward during the treatment period and even further forward during the long-term posttreatment period.
Conclusion: The outcomes of Herbst functional appliance in pharyngeal dimensions and hyoid bone position are stable over the years.