Understanding Correct Occlusal Adjustment: If Not Now, When?

Abstract

Introduction

A biomechanically acceptable occlusal plan is one that causes little altered function in the stomatognathic organ, and favours maintenance of an organized occlusion coupled with an organized disclusion to reduce or eradicate destruction to the dentition or its investing tissues. All teeth should close into a nonguided, nondeflective centric occlusion equally, firmly and simultaneously. The incisors should disclude all other teeth in protrusive movements, the canines should disclude all other teeth laterally. This arrangement promotes occlusal passivity.

Opposing parabolic surfaces are requisite for a scissor-like action of the cusps coincident with the curvature of the distal slope of the articular eminence, which determines the topography of the cusp between its tip and the base of the fossa. The angle of the slope determines the angle of the cusp. Convex occlusal surfaces, aided by concave maxillary palatal surfaces anteriorly, provide the greatest freedom of motion with the least amount of faceting. Flattened areas should not appear on occluding teeth, unless imposed by wear, accident or the -hand of man.

The teeth should not produce neuromascular contractual patterns that unconsciously avoid occlusal disharmonies. This produces stress in the masticatory muscles and ultimately will prcipitate bruxism. Correct organic occlusion is always the same; identical basic principles are involved for both young and old. Contrary to what some may believe, tooth wear is not a physiological phenomenon desirable with ageing. Cuspal wear is never desirable because the body does not replace shorn enamel and dentin. Wearing of teeth (faceting or bruxofaceting) is a gross symptom of musculoskeletal instability and abnormal function at any age.

Nothing else cripples a dentition so devastatingly - or so hobbles a chewing cycle with dysrhythmia - - as CR/CO disharmonies arising secondary to ill-conceived restorations that promulgate stress-inducing avoidance patterns. Since the occlusion of teeth can ostensibly influence the closing patterns of the mandibular musculature, dentists can easily initiate stress into the gnathic organ. Common dental procedures, which invariably alters the occlusal and incisal surfaces of opposing teeth, manipulate musculoskeletal proprioception in a manner entirely unique to dentistry. Thus, it behooves all dentists to be cognizant of deleterious wear patterns, and to understand, evaluate and be able to properly correct noxious occlusal interferences without further ablation of already-compromized dentate morphology. If not why, how? If not now, when?