Date of Award
Master of Science (MS)
Medical Sciences Interdepartmental Area
Purpose: The purpose of this investigation was to determine the volumetric and cross-sectional changes that may occur within the posterior pharyngeal airway space after positioning the mandibular condyles in centric relation.
Materials and Methods: All subjects evaluated presented signs and symptoms of upper airway obstruction with significant CR-CO discrepancies. Stabilization maxillary splint therapy was employed to seat mandibular condyles in CR. Pre- and post-treatment CBCT scans were taken to compare airway changes. Thirty-one subjects (13 male and 18 female) with a mean age of 45.8 years at the time of the post-treatment scan were evaluated. DICOM files were interpreted using Anatomage Invivo5 viewing software version. Airway measurements included total volume, nasopharynx volume, oropharynx volume, minimum cross-sectional area, and cross-sectional area at PNS, CV2, and CV3. The location of the minimum cross-sectional area was recorded in reference to the superior, middle, and interior thirds of the bodies of CV2 and CV3, and also the occlusal plane. A paired two-sample for means T-test was performed to determine the significance of change in volume and cross-sectional area. F-test was performed to determine the variability for gender with all measurements.
Results: Pre-treatment total mean volume was 11.92 cm3 and post-treatment total mean volume was 12.45 cm3, a mean difference of 0.53 cm3. Thirteen out of thirty-one subjects (42%) showed a decrease in total volume, whereas eighteen out of thirty-one (58%) exhibited an increase in total volume.The mean increase in total volume was not statistically significant (p=0.22). Pre- treatment means for cross-sectional area measurements at PNS, CV2, and CV3 were 466.1, 202.3, and 226.3 mm2, respectively. Post-treatment mean measurements at PNS, CV2 and CV3 were 474.9, 185.4 and 232.1 mm2, respectively. The mean differences between these pre-and post- measurements for PNS, CV2, and CV3 are 8.77, -16.89, and 5.82 mm2. These mean differences were not statistically significant (p=0.31, p=0.13, and p=0.34). Pre-treatment minimum cross-sectional area mean was 115.6 mm2 and post-treatment mean was 105.5 mm2. The mean difference was a -10.1 mm2, though this difference was not statistically significant (p=0.23). Differences between pre- and post- treatment minimum cross-sectional area locations were found on fourteen of the thirty-one patients (45%). Twenty-six of the thirty-one subjects (84%) displayed a minimum cross-sectional area located at either the superior, middle, or inferior third of the CV2 body. In addition, the minimum cross-sectional area was found to be inferior to the occlusal plane in twenty-eight of the thirty-one subjects (90%).
Conclusion: Positioning the mandibular condyles in centric relation does influence posterior pharyngeal airway volume and cross-sectional area; however, the dimensional changes are not statistically significant. Post-treatment mean total volume, oropharynx volume, and nasopharynx volume increased. Mean cross-sectional area at PNS and CV3 increased, while mean cross-sectional area at CV2 and minimum cross-sectional area decreased. Further studies are needed to assess the clinical efficacy of splint therapy to reduce severity and complications that arise from OSA.
Scott, Jason, "Evaluation of Posterior Pharyngeal Airway Volume and Cross-Sectional Area After Mandibular Repositioning in Centric Relation" (2015). Theses & Dissertations. 59.