Elnagar E I A, Allam G G, Khattab N M A
Department of Pediatric Dentistry, Faculty of Dentistry, Ain Shams University, Organization of African Unity Street, Cairo, Egypt.
Eur Arch Paediatr Dent. 2025 May 2. doi: 10.1007/s40368-025-01038-1.
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.
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.
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).
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.
Not applicable (in vitro study).
本体外研究旨在评估3D打印微填料混合树脂冠与预制氧化锆冠在乳磨牙牙髓切断术后的边缘间隙和抗折性。
选择20颗乳磨牙进行研究，并随机分为两组（n = 10）。第1组接受3D打印微填料混合树脂冠；第2组接受预制氧化锆冠。为模拟6个月的口腔条件，进行了热循环试验，并使用配备数码相机的立体显微镜在40倍放大倍数下测量边缘间隙。对于每个样本，在每个轴向表面的边缘沿线采集8个点。使用计算机控制的万能试验机对每组施加逐渐增加的载荷直至冠折，评估每组的抗折性。使用Shapiro-Wilk检验测试数据的正态性。使用独立t检验分析数据。显著性水平设定为P < 0.05。
关于抗折性，3D打印冠组的平均抗折性显著高于预制氧化锆冠组；数值分别为1235.97±412.12 N和576.56±221.53 N（P < 0.001）。然而，两种类型的冠之间的边缘间隙没有显著差异，3D打印冠的平均边缘间隙为32.00±7.54，氧化锆冠的平均边缘间隙为34.14±9.79（P < 0.001）。
3D打印微填料混合树脂冠可能是修复牙髓治疗后的乳磨牙的合适美观替代方案。有可能为家长/儿童提供额外的美观解决方案，以满足乳磨牙美观修复的需求。
不适用（体外研究）。
