# Evaluation of the Airway Space After Distalization in Adults Using the Carrière Motion Appliance: A Cone-Beam Computed Tomography (CBCT) Study

## TL;DR

This study uses CBCT scans to show that the Carrière Motion Appliance modestly increases airway space in adults undergoing dental distalization.

## Contribution

The study provides empirical evidence of airway space changes using CBCT scans with the Carrière Motion Appliance in adults.

## Key findings

- The total airway volume increased by 12.5% after distalization using the Carrière Motion Appliance.
- The minimum constricted area increased by 62.7% following treatment.
- The hypopharyngeal airway showed the largest volume gain at 78.7%.

## Abstract

Background: Distalization can be done with either intraoral (IO) or extraoral (EO) appliances and is one of the most prevalent methods for correcting class II molars. In recent decades, it has become more pervasive to treat class II malocclusions without taking teeth out. Persons with a neutro-basal jaw base relationship should distalize their teeth to make the dental arch wider in order to prevent the need to remove permanent teeth. The purpose of this investigation was to apply cone-beam computed tomography (CBCT) to examine how airway space changes in response to varying degrees of distalization.

Methods: Eighteen adult patients between the ages of 18 and 30 with complete dentition were instructed to wear the Carrière Motion Appliance (CMA) for four to six months. CBCT scans were obtained both before and after distalization for further evaluation. Pre- and post-distalization CBCT pictures were obtained for evaluation.

Results: This study's findings clearly show that Carrière Motion II improves airway volume (AWV) and minimum constricted area (MCA) to a modest degree. The TAV (total airway volume) increased significantly by 12.5% (from 39.9 ± 2.7 mL in pre-distalization to 44.9 ± 2.6 mL in post-distalization). Furthermore, the MCA increased significantly (at P ≤ 0.0001) by 62.7% between pre- and post-distalization. Airway volume measures of the nasopharyngeal, oropharyngeal, and hypopharyngeal levels also showed significant increments. Specifically, the nasopharyngeal, hypopharyngeal, and oropharyngeal airway volumes increased by 5.7%, 78.7%, and 15.6%, respectively.

Conclusions: The hypopharyngeal and oropharyngeal airways exhibit the largest volume gain compared to the nasopharyngeal airways. The upper TAV and MCA were clearly increased by the CMA.