A comparison of change in condylar position in asymptomatic volunteers utilizing a stabilization and a pivot appliance.

Although different occlusal appliances with various designs have been described in the literature, little is known about their influence on condylar position. The purpose of the present study was to compare the effect of two occlusal appliances (pivot appliance, stabilization appliance) on condylar position with respect to normal and maximum clenching force. Electronic-positioning-analysis was performed in 22 healthy volunteers with an ultrasound-based registration system. After randomized insertion of the appliances, the volunteers were asked to clench five times using normal and then maximum force. Data was compared using ANOVA for repeated measurements, with occlusal design and clenching force as covariables (alpha = 0.05). Insertion of appliances caused an anterior-downward movement of the condylar reference point (pivot appliance: 0.3 mm +/- 0.5 mm sagittally, 0.8 mm +/- 0.5 mm vertically; stabilization appliance: 0.2 mm +/- 0.5 mm sagittally, 0.8 mm +/- 0.5 mm vertically). In both appliances, maximum clenching force enhanced the anterior and reduced the downward position (pivot appliance: 0.4 mm +/- 0.5 mm sagittally, 0.6 mm +/- 0.5 mm vertically; stabilization appliance: 0.4 mm +/- 0.5 mm sagittally, 0.4 mm +/- 0.6 mm vertically). Within groups, the positions for normal and maximum clenching force were significantly different (p<0.001 in the sagittal and vertical dimension for both appliances). Comparison of occlusal design with respect to clenching force revealed no significant differences between both appliances. Insertion of both appliances induced an anterior-downward movement of the condylar reference point, whereas the two different occlusal designs had no influence on condylar position.