Fracture resistance of prefabricated versus custom-made zirconia crowns after thermo-mechanical aging: an in-vitro study

Background: Prefabricated zirconia crowns for a young permanent molar is a child-friendly solution for restoring a permanent molar at a young age. This in-vitro study aimed to compare the fracture resistance of prefabricated versus custom-made permanent molar crowns.Methods: 16 identical resin dies were fabricated to receive permanent molar zirconia crowns, dies were divided into 2 groups, 1) received perfricated crowns, 2) custom-made crowns. Thermo-dynamic cycling was performed to simulate 6 months in the oral cavity, Fracture resistance of each group was assessed by applying increasing load till fracture. Data were tested for normality using Shapiro-Wilk and Levene's tests. Data were analyzed using independent t test.Results: No statistically significant difference was found between fracture resistance of prefabricated and custom-made crowns (1793.54 +/- 423.82) and (1987.38 +/- 414.88) respectively. 3 crowns of the custom-made group fractured with the underlying die, versus zero dies fractured in the prefabricated group.Conclusions: Prefabricated permanent molars zirconia crowns can perform as well as custom-made crowns for an adult in terms of fracture resistance, it is suitable for children and can withstand the occlusal forces of an adult.

Automated summary

This study compared the fracture resistance of prefabricated and custom-made permanent molar crowns and found no significant difference between the two. There were more cases of crowns fracturing with the underlying die in the custom-made group. Prefabricated crowns can perform as well as custom-made crowns in children and withstand adult occlusal forces.