Given the potential usefulness of dental microwear analyses in interpretations of archaeological and paleontological material, it is surprising how little we know about changes in individual microwear features through time. The purpose of this study was to document the turnover in primate dental microwear through in vivo dental studies of monkeys raised on different diets, and through in vitro studies of the abrasive effects of monkey chow biscuits on isolated monkey teeth. As in previous studies, epoxy replicas were prepared from dental impressions and examined under a scanning electron microscope. Results indicate that, under certain conditions, the turnover in primate dental microwear can be on the order of days, hours, or even minutes. Individual microscopic wear features can be obliterated within 24 hours on the molars of laboratory monkeys, and monkey chow biscuits can easily scratch the enamel of isolated monkey teeth. Monkeys raised on a hard diet showed more rapid turnover in dental microwear than monkeys raised on a soft diet. However, paired-sample tests revealed that, for all animals, the molar shearing facets were being abraded at a significantly slower rate than molar crushing/grinding facets. In light of these results, investigators should make every effort to use large samples in interspecific comparisons of dental microwear involving species with variable diets. Another implication of these results is that changes in dental microwear might be useful indicators of changes in oral behavior over relatively short periods of time.

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Dental microwear analyses are beginning to provide new insights into the intricacies of jaw movement and tooth use in modern and extinct mammals. However, these analyses are also raising new questions that are best answered through studies of live animals with known diets. The process of taking dental impressions from live animals is a difficult one that presents problems different from those encountered in working with museum material. This report presents a review of some of those problems together with solutions that have been developed in the course of laboratory work with nonhuman primates. It also summarizes recent developments in dental casting.

The purpose of this study was to make detailed comparisons of rates and patterns of tooth wear in 15 growing vervet monkeys raised on hard vs. soft diets. Dental impressions were taken every six to eight weeks over a four-year period. Cusp heights and areas of dentin exposure on the buccal cusps of the left mandibular first molar were measured from high-resolution epoxy casts, by use of a Reflex Measuring Microscope. Areas of dentin exposure were regressed against time (by use of least-squares regression) so that the course of tooth wear in animals from both diet groups could be charted. By use of a two-sample t test and the Mann-Whitney test, slopes of the regressions and changes in cusp height were compared between diet groups. In both comparisons, animals raised on the hard diet showed more rapid tooth wear than did animals raised on the soft diet. Analyses of other parameters indicate that this was probably because of differences in dietary consistency between the two groups.