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.