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Changes of surface texture of enamel in vivo.

There are various methods of measuring tooth wear, including that which could be considered to be associated with acid erosion. However, the present systems are limited in that they require an extended period of study to detect wear and also they do not give any insight as to the underlying mechanism of the tooth tissue loss. The aim of this study was to use a profilometric measuring system analysing novel surface texture parameters normally associated with the automobile industry to describe the wear and run-in behaviour of machined sliding engine parts. The texture parameters selected were the traditional Ra parameter and also parameters derived from the bearing ratio. Analyses of the surface texture of the labial surface of upper central incisors at an interval of three months indicated that the enamel surface was smoother but there were subtle changes occurring to the enamel. There was a statistically significant increase in the depth of pits/pores of the enamel surface, which could be identified as sites of retention of exogenous acid or chelating agent. The effects of acid erosion are not uniform but are dependent upon several factors; the configuration of the enamel surface may play an important part in the mediation of acid erosion type lesions.