# Long-term evaluation (10 years) of the outcomes of Herbst functional appliance in pharyngeal dimensions and hyoid bone position

## TL;DR

This study found that the Herbst appliance improves and maintains pharyngeal space and hyoid bone position in Class II patients over 10 years.

## Contribution

The study provides long-term evidence of the Herbst appliance's effects on pharyngeal dimensions and hyoid bone position.

## Key findings

- The hipo pharynx space increased significantly during treatment and remained stable long-term.
- The hyoid bone moved forward and downward during treatment and continued forward post-treatment.
- Pharyngeal changes from the Herbst appliance are stable over a 10-year period.

## Abstract

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.

The sample comprised 15 skeletal Class II malocclusion patients (13.00 ± 1.21 years) treated with Herbst functional appliance and followed for a mean period of 10 years (10.73 ± 3.67 years). 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.

Regarding the pharyngeal cephalometric variables, only the hipo pharynx 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.

The outcomes of Herbst functional appliance in pharyngeal dimensions and hyoid bone position are stable over the years.