The relationship of the glenoid fossa to the functional occlusal plane.

The geometric relationship of the functional occlusal plane to the center of the glenoid fossa, as seen in the sagittal view, is described for males and females from age 7 through 25 years. This relationship is fully described by the distance from the geometric center of the glenoid fossa perpendicular to the functional occlusal plane (L, in millimeters) and its angulation (theta, in degrees) relative to a constructed Frankfort horizontal (SN-7 degrees ). Regression formulas with 95% confidence levels are described for L and theta for both genders combined. The differences between genders were found to be statistically insignificant. No correlation was found between these dimensions relative to the presence of temporomandibular joint dysfunction symptoms. A statistically significant difference in both L and theta was found in males who exhibited a Class III relationship compared with males exhibiting a Class II relationship.