Wear resistance and hardness of a polymethyl methacrylate pearls modified artificial resin tooth

Abstract

Objective The purpose of this study was to evaluate the wear resistance and hardness of a polymethyl methacrylate (PMMA) pearls modified artificial resin tooth compared to five commercially available denture teeth. Methods Eight specimens of six different artificial resin teeth (3 highly cross-linked acrylic resin teeth: Vita Lingoform, Premium and Portrait IPN; 2 composite resin teeth: Yamahachi PX and Huge Kaiplus and 1 conventional acrylic resin teeth Yamahachi FX) were tested. One of the artificial resin teeth (Vita Lingoform) is a new PMMA pearls modified denture teeth. Human enamel was used as a control group. The specimens were mounted to a high temperature fretting abrasive tester with a pin-on-block design, and the vertical loss and volume loss of the samples were measured using three-dimensional surface profilometer. Hardness of the samples was determined using a micro-Vickers hardness tester. Data of wear loss and Vickers hardness were statistically analyzed with the Kruskal-Wallis H nonparametric test and the Spearman correlation coefficient was used to determine the relationship between the wear loss (vertical loss and volume loss) and hardness. Results The six artificial resin teeth and human enamel tested showed significant differences in the vertical loss (μm) and volume loss (mm3×10-3) (Hvertical loss= 95.01, Hvolume loss= 93.96, P 0.05) . The human enamel group revealed the highest wear resistance and Vickers hardness values (0.31, 0.213; 68.2, P<0.001) among all the materials tested. Moreover, A negative relationship was found between hardness and vertical loss (r=-0.896) and volume loss (r=-0.893) . Conclusions The PMMA modified artificial resin teeth revealed improved wear resistance and hardness values compared to the conventional acrylic resin denture teeth. However, it showed less wear resistance and hardness values than the composite resin teeth and human enamel. No significant differences were found for the wear loss and hardness values among the three highly cross-linked artificial resin teeth. Key words: Hardness; Artificial resin teeth; Wear resistance; Wear loss