DEVELOPMENT OF A NOVEL SYSTEM FOR ASSESSING TOOTH AND RESTORATION WEAR

Objectives: This investigation sought to develop a mapping apparatus f or use in the assessment of both tooth and restoration wear. Methods: A computer controlled mapping device, capable of scanning a suitably p repared electroconductive tooth replica by means of an electrical Feed back mechanism, was constructed and its accuracy assessed by measuring the thicknesses of four engineers' slip gauges 12 times each. The rep roducibility of three potential methods of rendering a die stone repli ca electroconductive was also investigated. Finally, tooth replicas we re surface profiled and compared empirically with the originals using a commercial surface mapping program. Results: The overall mean accura cy of the mean thicknesses of the slip gauges was 4.4 (2.8) mu m. Surf ace deposition of either nickel spray or gold leaf, upon a ready forme d replica, did not give a reproducible thickness, Precoating silicone impressions with nickel spray prior to replica production overcame thi s problem. On an empirical basis the instrument yielded accurate digit al terrain models of tooth replicas. Conclusions: A surface mapping de vice has been developed which is both accurate and reproducible. A sat isfactory electroconductive surface may be produced upon a tooth repli ca by precoating a silicone impression with nickel spray before castin g the replica, The technique should prove invaluable for monitoring bo th tooth and restoration wear but further work is necessary to examine how such an approach will perform clinically. (C) 1997 Elsevier Scien ce Ltd.