Pharyngeal airway volume changes following treatment of skeletal class II patients using a miniplate-supported buccally acting distalizer: A retrospective 3-dimensional CBCT study

Abstract

Objective: To evaluate pharyngeal airway volume changes following treatment of skeletal class II patients using miniplate supported buccally acting distalizer; Zyogoma Anchorage System (ZAS) using cone beam computed tomography (CBCT). Materials and Methods:Ten class II patients (8 females and 2 males), with a mean age, 13.44 ± 1.08 years were treated by ZAS. ZAS consists of two zygomatic miniplates, a heavy arch wire, and a closed Nickel Titanium (NiTi) coil spring attached between a power hook on 0.018 × 0.025-inch stainless steel arch wire stepped on the six anterior teeth mesial to the maxillary 1 st premolar and the hook of a miniplate supported to zygomatic buttress of each side. The spring delivered 450 gm continuous force. The volumetric air way changes concomitant to maxillary buccal segments distalization and the sagittal skeletal parameters before and after distalization were analyzed based on CBCT images.Results: Paired sample t-test showed a statistically highly significant (p≤0.01) increase (3.16 cm 3 , 0.78 cm 3 ) in both total airway and nasopharyngeal airway volumes respectively with treatment, whereas retropalatal airway volume showed statistically significant (p≤0.05) increase (0.96 cm 3 ) after treatment with the skeletally anchored distalizing appliance. But retroglossal airway volume showed statistically non-significant (p>0.05) increase (0.81 cm 3 ) with treatment. Moreover, an improvement in class II correction was evident as demonstrated by a statistically highly significant (p≤0.01) increase (4.38 mm, -3.94 mm) in MBCU6-Nv and MBCU6-ptv respectively.Conclusions: Pharyngeal airway volume considerably enhanced subsequent to skeletal class II correction through the miniplate supported distalizer appliance which could be a helpful treatment opportunity for skeletal class II patients who have breathing disorders.