Enamel wear evolution: Evaluation using statistical mixed models for 2D profilometry data

Abstract

Two-dimensional profilometry is an inexpensive well-established technique to identify indicators of tooth wear. Four surface parameters ( Ra, Rq, Rsk, and Rku) were selected in this work to evaluate worn dental surfaces using two-dimensional profilometry. Eight subjects with dental wear were molded four times with a 15 days interval. To verify data correlation, a mixed-effects model was adjusted. The results indicated that Ra, Rq, Rsk are time dependent, while Rku remained constant. Rsk and Rku values were useful to identify surfaces. Skewness had oscillatory variations and Rku was tending toward a constant rate for a longer period. Two regimens were suggested: (1) transient and (2) self-limiting. Final variation rates indicated that, although enamel wear transiently modifies the surface, it maintains its isotropic characteristic: symmetrical and approximately normal asperities distribution.