Treatment effects of two different appliances on pharyngeal airway space in mixed dentition Malay children

BACKGROUND: Treatment of Class III malocclusion is related to redirecting the growth of mandible, which may have an impact on the pharyngeal airway.

OBJECTIVE: To evaluate and compare the treatment effect of Reverse Twin-Block (RTB) and Reverse Pull Face Mask (RPFM) on Pharyngeal Airway Space (PAS) in early and late mixed dentition Class III samples.

METHODS: Ninety-five mixed dentition Malay children with Class III malocclusion were included in this study. Data consists of 190 pre- and post-treatment lateral cephalograms of early (8-9 years) and late (10-11 years) mixed dentition Class III samples. forty-nine samples were under RTB and forty-six samples were under RPFM. Treatment changes were evaluated by McNamara airway analysis and changes in tongue and hyoid bone position.

RESULTS: Both upper and lower pharyngeal airway width were increased after treatment with RTB and RPFM ruling out the chance of airway constriction. There was also posterior positioning of the tongue and hyoid bone indicating mandibular retrusion. No significant treatment changes were found on the Pharyngeal Airway Space by the factor age, gender or type of appliance.

CONCLUSIONS: Both RTB and RPFM increased the Pharyngeal Airway Space and produced similar treatment effect. As age does not affect the treatment outcome significantly, treatment can be delayed until late mixed dentition stage.