Artificial Enamel Wear after Prolonged Chewing Simulation against Monolithic Y-TZP Crowns

Abstract

The aim of this study was to evaluate the effect of chewing simulation on wear of artificial enamel abraded against zirconia-based crowns. Fifteen crown preparations were scanned for the manufacturing of crowns using computer-aided-design/computer-aided-machining technique (CAD/CAM), according to the following (n = 5): Polished (PM) and glazed (GM) monolithic zirconia (1.5 mm uniform thickness), and Bilayer (BL -0.8 mm zirconia coping, 0.7 mm porcelain veneer) crowns. The samples were cemented and chewing simulation (2.5 million cycles/0-80N/artificial saliva/37˚C) was performed with steatite indenters (6 mm diameter) as antagonists. Assuming the uniformity of the unaged samples, antagonists were scanned using a surface profilometer and the material loss volume was calculated. Roughness of the crowns' occlusal surface was also analyzed using the profilometer. Scanning electron microscopy was used to characterize the abraded surface. One-way ANOVA and Tukey test (p = 0.05) were employed for analysis of wear results. A significant difference was observed among the groups (p < 0.001). Artificial enamel abraded against porcelain (BL) had significantly higher material loss (0.217 mm 3 ± 0.015) than those abraded against monolithic zirconia, polished (PM -0.167 mm 3 ± 0.02) and glazed (0.101 mm 3 ± 0.03), which were similar to each other. Veneering porcelain results in more pronounced wear of the artificial enamel than monolithic zirconia. However, mastication against monolithic Y-TZP also imposes wear to the opposing teeth.

Irradiation therapy and chewing simulation: effect on zirconia and human enamel

“…A rougher surface increases wear pattern of opposing enamel [23]. Previous studies found that polishing zirconia results in a surface smoother than glazing [15], but polished zirconia seems to be more deleterious to the wear of artificial enamel when compared to glazed zirconia and bi-layer (zirconia-porcelain) restorations [17]. All zirconia specimens were polished up to 1 µm in the present study.…”

“…Monolithic Y-TZP meets the demands of patients and dentists for a tooth-colored, strong and biocompatible restorative material, and it provides for proper intraoral function in both anterior and posterior regions [9,14,15]. Previous studies have demonstrated that polished zirconia causes less wear to the opposing enamel surface than enamel itself, glazed zirconia [16,17] and other ceramics such as lithium disilicate glass, leucite-reinforced glass and feldspathic porcelain [18]. Occlusal adjustments of zirconia after insertion are considered of clinical concern due to changes in surface roughness and crystalline structure of zirconia [19][20][21][22], and also because it might affect the wear pattern of the opposing enamel [23].…”

The Effect of Simulated Chewing on the Surface Roughness of Direct and Indirect Resin‐Composites Opposed by Zirconia: An In Vitro Study

“…In the literature, many studies have reported on the wear effect of different restorative materials antagonizing enamel [ 5 , 22 , 28 ]. However, there is limited data describing the wear characteristics and interaction of different types of restorative materials opposing each other, representing a situation that is encountered in daily clinical practice when restoring dentitions.…”