Discussion of “laws of articulation”

Abstract

I agree in part with both Hanau's and Trapozzano's concepts of the laws of occlusion. 1. I see three fixed factors instead of one, with the orientation of the occlusal plane and the incisal guidance angle being additions to the condylar guidance as fixed factors. 2. The angulation of certain cuspal inclines is more important than the height of the cusps per se. 3. The compensating curve is a device for increasing the effective height of the cusps without changing the forms of the individual teeth. 4. Both the cusp height and the compensating curve are means for solving the problems imposed by the Christensen phenomenon. They are the means whereby the space developed at the posterior end of the occluding surfaces which results from the downward movement of the condyles can be closed by tooth contacts. 5. The occlusal plane should be oriented according to esthetic appearance and intraoral soft tissue anatomy (the retromolar pads and tongue) instead of located according to leverage or mechanical requirements. 6. The orientation of the occlusal plane, i.e., the angle of its deviation from the horizontal, does have an effect upon the things that must be done to the angulation of the cuspal inclines, either by tipping the teeth into a compensating curve or the choice of a posterior tooth form. 7. Dr. Trapozzano's diagram can be helpful toward an understanding of the relationship of the tooth surfaces to the end guidances. In closing, I wish to thank Dr. Trapozzano for stimulating me to put these ideas on paper. I feel certain that he has stimulated the reader as well.