Wear of resin teeth opposing zirconia

Statement of problem: The use of dissimilar materials for opposing complete-mouth implant-supported prosthesis has become popular, especially when one arch is made from anatomical contour zirconia. However, the amount of wear zirconia causes on resin and other denture tooth materials is largely unknown.

Purpose: The purpose of this in vitro study was to determine the volumetric wear of 4 commercially available resin materials used for denture teeth in complete-arch implant-supported prostheses opposed by zirconia.

Material and methods: A total of 32 maxillary central incisor denture teeth were evaluated (n=8): double crosslinked polymethyl methacrylate (PMMA) (DCL), nanohybrid composite resin (PHO), and computer-aided design and computer-aided manufacturing (CAD-CAM)-fabricated teeth made from crosslinked PMMA (TEL) and acrylate polymer (ZCAD). Antagonist cone-shaped specimens were milled from zirconia. Specimens were mounted in acrylic resin, polished to a flat surface by using 1200-grit SiC paper, and stored in water (37 °C for 24 hours) before exposure in a custom dual-axis wear simulator for 200 000 cycles with a vertical load of 20 N, a horizontal slide of 2 mm, and a frequency of 1 Hz. Volumetric wear was measured by using a noncontact profilometer and a superimposition software program. Data were analyzed with a 1-way analysis of variance (ANOVA) and the Tukey Honestly Significant Difference (HSD) post hoc test (α=.05).

Results: A statistically significant difference in volumetric wear was found between groups (P<.001), with PHO (4.3 ±1.0 mm³)<TEL (11.9 ±2.0 mm³)<ZCAD (14.2 ±0.8)<DCL (17.3 ±1.0 mm³).

Conclusions: Denture teeth made from different materials demonstrate significantly different volumetric substance loss when subjected to occlusal wear by zirconia antagonists. Nanohybrid composite resin denture teeth had the least amount of volumetric substance loss.