The measurement of wear in dental restorations using laser dual-source contouring

Abstract The development of a technique for the accurate measurement of wear during the use of dental restorations is described. Measurements were made by comparing suitable impressions of the restorative and surrounding area before and after test. Detailed information about the topology of the pre-wear and post-wear restoratives obtained from contour maps of the impressions was processed to find the volume lost by the restoration during test. The technique, an extension of earlier experiments, relies on the precise reproduction of dental surfaces by the impression material used. The accuracy and precision of vinyl polysiloxane was investigated and found to be adequate. Three methods of interpreting the contour maps are presented, including a computer technique, for the estimation of volume loss. The computer technique also produces “difference” contour maps of the wear scars. Calibration tests on extracted teeth showed that volume loss due to wear can be measured to an accuracy of between 2% and 10% depending on the data-processing technique used.