THE CORRELATION OF THE INCLINED PLANES OF THE ARTICULAR SURFACE OF THE GLENOID FOSSA WITH THE CUSPAL AND PALATAL SLOPES OF THE TEETH

¹ Department of Physiology and Division of Dental Research, Faculty of Medicine, Columbia University, New York, N. Y.

1. The construction of a measuring device and the method of recording anatomic structures are described.

2. The articular slope of 20 fossae and the cuspal and palatal slopes of the maxillary teeth in 10 skulls were studied in order to determine if any correlation between these units existed. The skulls selected had to conform with the following requirements: normal occlusion, nonabraded cusps, and an amount of overbite between 1 to 5 millimeters. Within these limitations of control, the skulls were chosen at random.

3. The anterior slope of the fossa and the inclined planes of the cusps and palatal slopes were measured and recordings made. Their slopes were determined in units of degrees.

4. The collected data were subjected to statistical analysis which gave the following results: (a) The anterior slope of the glenoid fossa shows great individual variation both within the sample group and within each skull; (b) The teeth exhibit a greater constancy in their inclined planes and show less variation between the two sides of one and the same skull, although the palatal slopes of the upper anterior teeth show greater individual variations than the cuspal slopes of the posterior teeth; (c) No significant difference was found between the main slope of the articular surface of the glenoid fossa and this of the palatal slope of the upper anterior teeth, although the mean cuspal slope was found significantly different; (d) The correlation found between the articular slopes of the fossae and the dental slopes (both cuspal and palatal) appears significantly different from zero at the 0.05 level; (e) All the statistical methods applied seem to indicate a closer relationship between the articular slope of the fossa and the palatal slope of the upper anterior teeth, the correlation to the cuspal inclines of the posterior teeth being less significant; and (f) On the basis of this study alone no definite conclusions can be made if and to what extent the teeth have a functional influence upon the configuration of the articular surface of the glenoid fossa.