Semester

Spring

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Orthodontics

Committee Chair

Richard Jurevic

Committee Co-Chair

Chris Martin

Committee Member

Peter Ngan

Abstract

Introduction: The unilateral posterior crossbite with a functional shift is one of the most common early adolescent malocclusions. It is caused by a transversely deficient maxilla, relative to the mandible, and results when the mandible shifts to one side to so the teeth can maximally interdigitate. This shift is thought to cause the contralateral condyle to move anteriorly, inferiorly, and medially within the TMJ. Much attention has been given recently to the affects of this functional shift on the condyles. An attempt is being made to determine if pathological position of the condyles can cause condylar signs or symptoms similar to DJD or JCR, or if the position of the condyle is in an altered position within the TMJ. Methodology: Sixty DICOM images were reviewed from the private database of Thomas Shipley D.M.D., M.S. of Peoria, AZ. Thirty one subjects were selected for the control group and twenty nine subjects were selected based on a unilateral posterior crossbite with a functional shift. Transverse dimensions were measured at the skeletal base and the dentoalveolar base. Molar inclinations, condylar angulations, and condylar anterior joint spaces, superior joint spaces, and posterior joint spaces were measured. ANOVA was used to compare different groups and matched pair was used to compare differences within the same patient. Pairwise correlation was used to determine reliability. Results: The dentoalveolar measurements concluded our crossbite group had a maxillomandibular difference of -8.22mm +/- 3.04 and our control group had a difference of -4.01 +/- 2.69. There were no statistical differences between molar inclinations, condylar width or angulation, or any joint space measurements. 19/31 of the control group, and 21/29 of the crossbite group had a radiographic sign of joint disease. Conclusion: Since there were no positional differences in the condyle between the control and crossbite groups, some sort of remodeling that occurs within the TMJ would likely have to occur.

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