Airway and cephalometric changes in adult orthodontic patients after premolar extractions.

OBJECTIVE: To examine changes in the airway and cephalometric measurements associated with orthodontic treatment of adults with and without premolar extractions. The study investigated whether extractions had a direct or indirect effect on the airway and examined selected skeletal and dental features. MATERIALS AND METHODS: This retrospective study used pre- (T1) and posttreatment (T2) cone-beam computed tomography scans of 83 adult patients matched for age and sex. A total of 15 airway and 10 skeletal and dental measures were analyzed by means of repeated-measures analysis of variance. RESULTS: There were no results showing that extractions affected airway dimensions that could not be accounted for as reflections of measurement error. There was no evidence that extractions affected the airway indirectly through skeletal and dental changes. There were strong and consistent findings that patients with small airways showed larger ones after treatment and that patients with large airways showed smaller ones later. These effects were independent of whether or not extractions were part of treatment. The measurement phenomena of regression toward the mean and of differential unfolding of natural changes over time could have accounted for the results observed. CONCLUSIONS: There was no evidence that extractions in nongrowing patients have negative consequences on the size of various airway measures in the nasopharynx, retropalatal, or retroglossal regions.

A three-dimensional comparison of the pharyngeal airway after mandibular distraction osteogenesis and bilateral sagittal split osteotomy.

PURPOSE: The goal of this retrospective study was to examine the radiological changes in the pharyngeal airway following mandibular distraction osteogenesis (DO) and bilateral sagittal split osteotomy (BSSO). MATERIAL AND METHODS: Between 2005 and 2009, a total of 41 nonsyndromic patients underwent a mandibular osteotomy (nDO = 23; nBSSO = 18). Digital volume tomography images were created for preoperative and postoperative evaluations of both groups. The Dolphin 3D program was used for comparative analysis of the pharyngeal airways. RESULTS: After DO, the airway volumes (VOL) improved by 6.8 mL. In comparison, an improvement of 5.9 mL was observed as result of BSSO. The minimum axial areas (AREA) of the enlargements increased by 109.1 mm(2) with DO and 103.1 mm(2) with BSSO. The airway areas (SA) increased by 193.8 mm(2) with DO and 185.2 mm(2) with BSSO. There were no significant differences between two surgical procedures in terms of the parameters describe above (pVOL = 0.358; pAREA = 0.752; pSA = 0.777). However, the initial preoperative values (pVOL = 0.020; pAREA = 0.005) and the patients' ages (pAREA = 0.042; pSA = 0.007) did have significant effects on the postoperative values. CONCLUSION: Both DO and BSSO expanded the pharyngeal airways of all nonsyndromic patients.

Effects of mandibular advancement surgery combined with minimal maxillary displacement on the volume and most restricted cross-sectional area of the pharyngeal airway.

The purpose of this study was to evaluate changes in the volume and most restricted cross-sectional area of the pharyngeal airway as a result of mandibular advancement surgery with minimal maxillary displacement, and to ascertain the change in height of this restricted area and whether gender and age could influence these results. Cone beam computed tomography scans were obtained from 25 patients (seven male and 18 female, average age 35.5 years). The measurements were done using the InVivoDental software (version 5.0). Comparisons were made between measurements taken prior to treatment (T1) and postsurgery (T2, average 6.3 months after surgery). No variation was detected on the scans with regard to head position, which could influence the pharynx airway. Surgery significantly increased the pharynx airway volume at the total (P<0.0001), upper (P=0.0001), and lower (P<0.0001) levels, with respective enlargements of 54.5%, 37.0%, and 91.3%. Gender and age did not influence this increase. A significant enlargement in the minimum area of the pharynx airway was detected (P<0.0001), which changed in shape from a tapering to a rounded shape. Using binomial and multiple logistic regression tests, this constricted site presented an unpredictable change in position as a result of surgery, with no association to gender (P=0.0745) or age (P=0.5879).