Evoked potentials: By Konrad Maurer, Klaus Lowitzsch, and Manfred Stohr. 177 pages. $49.00. Philadelphia: B.C. Decker, 1989

Abstract

Statement of problem. Wear of human enamel is a clinical concern whenever opposing teeth need to be restored using ceramic restorations. Purpose. This in vitro study investigated wear of human enamel and 3 dental ceramics: a conventional porcelain (Vitadur Alpha), a low-fusing hydrothermal ceramic (Duceram-LFC), and a machinable ceramic (Vita Mark II) in a 3-body wear test. Material and methods. Thirty pairs of tooth-ceramic specimens were tested in a dental wear machine, under a standard load (40 N), rate (80 cycles/minute), and for 25,000 cycles in a simulated food slurry medium. Amount of wear was determined by measuring the height loss of the tooth and depth of wear track of the ceramic materials. Analysis of variance (ANOVA) was used to analyze the data, followed by Bonferroni multiple comparisons method to produce sets of simultaneous 95% confidence intervals. Results. ANOVA revealed significant differences between the groups for both enamel wear (P =.002) and ceramic wear (P <.001). Further comparisons (95% CI significance level) revealed that the difference in enamel wear produced by Alpha porcelain and Duceram-LFC ceramic material was not statistically significant, whereas that produced by Vita Mark II ceramic was significantly less. Vita Mark II ceramic was significantly more resistant to wear than Alpha porcelain and Duceram-LFC ceramic. Furthermore, Alpha porcelain was significantly more resistant to wear than Duceram-LFC ceramic. Conclusion. The abrasiveness of Alpha porcelain and Duceram-LFC ceramic was similar, yet both were significantly more abrasive than Vita Mark II ceramic. In addition, Vita Mark II was the most wear resistant ceramic and Duceram-LFC ceramic the least resistant. (J Prosthet Dent 1999;82:476-81.)