Wear Resistance Comparison of Prefabricated Primary Crowns Using a Novel 3D Computed Tomography Method.

PURPOSE: The purpose of this study was to compare the wear resistance of stainless steel crowns, (SSCs), zirconia crowns (ZRCs), and nanohybrid crowns (NHCs) using a 3D tomography method.

METHODS: Prefabricated SSCs, ZRCs, and NHCs (n equals 80) were worn for 400,000 cycles, equivalent to three years of simulated clinical wear, at 50 N and 1.2 Hz using the Leinfelder-Suzuki wear tester. Wear volume, maximum wear depth, and wear surface area were computed using a 3D superimposition method and 2D imaging software. Data were statistically analyzed using one-way analysis of variance with the least significant difference post hoc test (P<0.05).

RESULTS: After a wear simulation of three years, NHCs had a 45 percent failure rate; NHCs also had the greatest wear volume loss (0.71 mm³), maximum wear depth (0.22 mm), and wear surface area (4.45 mm²). SSCs (0.23 mm³ , 0.12 mm, 2.63 mm²) and ZRCs (0.03 mm³ , 0.08 mm, 0.20 mm ²) had less wear volume, area, and depth (P<0.001). ZRCs were the most abrasive to their antagonists (P<0.001). The NHC (against SSC wearing group) had the greatest total wear facet surface area (4.43 mm²).

CONCLUSIONS: Stainless steel crowns and zirconia crowns were the most wear-resistant materials. Based on these laboratory findings, in the primary dentition, nanohybrid crowns are not recommended as long-term restorations beyond 12 months (P=0.001).