Cusps or no cusps--that is not the question.

Abstract

Current views of the significance of cusps to oral health range from an emphasis on meticulous recusping of the restored teeth to a recommendation of gradual prophylactic elimination of natural cusps by grinding. Cusps, their morphology and mutual arrangement are associated with masticatory function. The adaptive value of efficient mastication has diminished along with advancing cultural evolution. Industrialization marks a turning point as seen from the almost total disappearance of functional tooth wear. Restoring cusps to achieve maximum structural efficiency thus lacks a rational basis. But the occlusal morphology is also associated with the swallow reflex: retrusive occlusal interferences tend to disturb it. These interferences can be avoided by establishing the freedom in centric or by restoring the occlusion to the retruded position. The prophylactic grinding of teeth also lacks a rational basis. The consequences of artificial wear are not likely to be the same as those of functional wear because the function has changed, the oral environment is different. It seems advisable, therefore, to try to eliminate only unquestionably harmful factors, and to leave the rest of the morphology as unchanged as possible.