The influence of cyclic loading on the wear of a dental composite

The load applied to a tooth surface during mastication is not a constant fo rce and the objective of the research reported in this paper was to evaluat e the impact of variable masticatory loads on the mechanisms involved in th e wear of a dental composite. A new wear testing machine has therefore been developed, which incorporates a sine cam mechanical system to generate an alternating sine curve load at the wear surfaces to simulate the loading pr oduced by masticatory process. The basic wear pattern is generated by posit ioning a disc shaped specimen against a rotating cylindrical ring with a no rmal load applied to the upper surface of the specimen. This approach allow s different combinations of static and sine curve loads to be applied, ther eby facilitating the study of different wear situations. It was found that the wear behaviour associated with variable loading patterns differed from that of static loading. (C) 1999 Elsevier Science Ltd. All rights reserved.