Novel 3D printed resin crown versus prefabricated zirconia crown for restoring pulpotomized primary molars: in vitro evaluation of fracture resistance and marginal gap.

Abstract

Aim: This in vitro study aimed to evaluate the marginal gap and fracture resistance of 3D printing microfilled hybrid resin crowns in comparison to prefabricated zirconia crowns on pulpotomized primary teeth.

Materials and methods: Twenty primary molars were selected for the study and randomly divided into two groups (n = 10). Group1 received 3D printed microfilled hybrid resin crowns; Group 2 received prefabricated zirconia crowns. To simulate 6 months of oral conditions, thermodynamic cycling was performed, and the marginal gap was measured using a stereomicroscope with digital camera at 40 × magnification. For each sample, eight points along the margins for each axial surface were captured. The fracture resistance of each group was assessed by applying increasing load till crown fracture using a computer-controlled universal testing machine. Data were tested for normality using the Shapiro-Wilk test. Data were analyzed using an independent t test. A significant level was set at P < 0.05.

Results: Regarding fracture resistance, 3D printed crowns group had statistically significant higher mean values than the prefabricated zirconia crowns group; the values were 1235.97 ± 412.12 N and 576.56 ± 221.53 N, respectively (P < 0.001). However, there was no significant difference in the marginal gap between the two types of crowns with average 32.00 ± 7.54 for 3D printed crowns and average 34.14 ± 9.79 for zirconia crowns (P < 0.001).

Conclusion: 3D printed microfilled hybrid resin crowns could be a suitable esthetic alternative for restoring pulp-treated primary molars. It is possible to provide an additional esthetic solution for the parents/children to satisfy the need for esthetic restoration of primary molars.

Clinical trial: Not applicable (in vitro study).