Graduation Date

Fall 12-18-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Programs

Medical Sciences Interdepartmental Area

First Advisor

Sheela Premaraj

Second Advisor

Sundaralingam Premaraj

Abstract

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.

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