Comparison of wear behavior of 3D printed permanent resin, milled zirconia, and primary tooth enamel on antagonist primary canines: in vitro study

BACKGROUND: Data comparing the wear of 3D printed permanent resin (PR) and milled zirconia (Z) to that of primary tooth enamel are limited. This study aimed to investigate the wear behavior of two materials and their effect on antagonist primary canine, in comparison with primary tooth enamel. METHODS: Milled monolithic Z (IPS e.max ZirCAD Prime Esthetic, Ivoclar), and PR (Permanent Crown Resin, Formlabs), and primary central incisor enamel (PCIE) (per group n = 15) as the control group were included in the study. Z and PR were polished by intraoral polishing set (Optragloss, Ivoclar Vivadent). Two-body wear tests were performed in a chewing simulator for all specimens, with primary canines used as antagonists (50 N, 1.2 × 10⁵ cycles, 1.56 Hz, 5/55°C). Wear volume and wear depth were assessed by overlapping the data before and after the chewing test with a software program (Geomagic Control X). Vickers hardness tests were performed (n = 10) for both materials. Data were analyzed statistically with one-way ANOVA (p < 0.05). RESULTS: For each group, n = 9 specimens were able to complete 120,000 cycles. The results showed that the PR exhibited the highest volume loss, while Z had the lowest wear depth (p < 0.05). When we examined the antagonist teeth, the highest volume loss was observed in the Z group (p < 0.05), but there was no significant difference in wear depth (p = 0.079). The Vickers hardness of Z was significantly higher than that of the PR (p < 0.05). CONCLUSION: Both highly polished monolithic Z and PR demonstrated comparable antagonist wear to that of PCIE; however, while PR showed a similar wear resistance to PCIE, Z exhibited the highest resistance overall. CLINICAL SIGNIFICANCE: PR demonstrated wear resistance similar to primary tooth enamel under the conditions of this study, suggesting it may be a suitable option for pediatric restorations where antagonist wear is a primary concern. However, additional properties require further evaluation.