Evaluation of Wear Resistance and Surface Roughness of Preformed Zirconia Crowns vs Stainless Steel Crowns on Extracted Primary Molars

Aim: To compare the in vitro wear resistance and surface roughness (Ra) of preformed zirconia crowns (PZCs) and stainless steel crowns (SSCs) on extracted primary molars.Materials and methods: A total of 59 primary molars extracted for therapeutic reasons were selected and randomly allocated into two groups: group I (n = 30)-PZCs, and group II (n = 29)-SSCs.All crowns were luted using glass ionomer cement and subjected to chewing simulation for 1,00,000 cycles under 50 N load at 37C in artificial saliva.Surface roughness (Ra) was assessed using a contact profilometer before and after simulation, and wear resistance was evaluated by weight loss analysis (precision microbalance).Using paired t-test and independent t-test with significance at p < 0.05, the data were evaluated.Results: Mean surface roughness increased significantly after simulation in both groups, but PZCs exhibited lower roughness (Ra = 0.42 0.08 m) compared to SSCs (Ra = 0.63 0.11 m) (p < 0.001).Wear resistance was superior in PZCs with less material loss (1.25 0.23 mg) than SSCs (2.14 0.32 mg).Conclusion: Preformed zirconia crowns demonstrate significantly better wear resistance and lower surface roughness compared to SSCs.Clinical significance: Preformed zirconia crowns demonstrated significantly better wear resistance and lower surface roughness compared to SSCs, making them suitable for esthetic crowns.