Assessment of optimal condylar position with limited cone-beam computed tomography

Introduction: There are no quantitative standards for the optimal position of the mandibular condyle in the glenoid fossa. Recently developed limited cone-beam computed tomography (LCBCT) allows measurement of this position with high accuracy. Methods: LCBCT was used to assess 24 joints in 22 symptom-free subjects (10 male, 12 female; mean age, 18 years) who had no disc displacement as verified by magnetic resonance imaging. Their joints had optimum function with the starting and end points of all functional jaw movements coincident with maximum intercuspation. Linear measurements of anterior space (AS), superior space (SS), and posterior space (PS) were made to determine the position of the condyle for each joint. Results: The mean AS, SS, and PS values were 1.3 mm (SD +/- 0.2 mm), 2.5 mm (SD +/- 0.5 mm), and 2.1 mm (SD +/- 0.3 mm), respectively. The ratio of AS to SS to PS was 1.0 to 1.9 to 1.6. No significant sex difference was noted in joint space distances. The results showed less variability of condylar position in the fossa than previously reported in normal subjects. Conclusions: These data from optimal joints might serve as norms for the clinical assessment of condylar position obtained by LCBCT. (Am J Orthod Dentofacial Orthop 2009;135:495-501)