Abstract: Objective    To evaluate the fracture resistance and marginal adaptation of different material inlays after restoration of isolated primary molars. Methods    Totally 55 freshly extracted mandibular second primary molars with complete crowns and root absorption of no more than 2/3 were collected and prepared as specimens using acrylic resin blocks. Ten specimens were used as the control group and the remaining specimens were divided into 3 groups after the preparation of Class Ⅱ cavity inlays（15 in each group）. Three different materials were used to complete the inlay restoration（Group A：IPS e. max CAD；Group B：Lava Ultimate；Group C：BioPAEK）. The fracture resistance immediately after restoration，fracture resistance after thermal cycling，and marginal adaptation after thermal cycling were detected，and comparative analysis was made. Results    Immediately after restoration，the fracture resistance of the 4 groups were （1527 ± 21.06）N in group A，（1616 ± 23.85）N in group B，（1580 ± 19.63）N in group C，and （1643 ± 19.60）N in the control group. The fracture resistance of group A and C were significantly lower than the fracture resistance of the control group（P < 0.05），the fracture resistance of group B was not statistically different from the fracture resistance of the control group（P > 0.05），and the fracture resistance of group B and C were both significantly greater than the fracture resistance of group A（P < 0.05）. The fracture resistance of the 4 groups after the thermal cycling were （1477 ± 29.44）N in group A，（1567 ± 24.17）N in group B，（1484 ± 23.33）N in group C，and （1608 ± 26.45）N in the control group. The fracture resistance of group B was significantly higher than that of group A and group C（P < 0.05），which was not statistically different from the control group（P > 0.05）. Dye penetration depth on the axial wall of the 3 groups after thermal cycling：group A（0.20 ± 0.02）mm，group B（0.21 ± 0.01）mm，group C（0.20 ± 0.02）mm；dye penetration depth on the gingival wall of the 3 groups after thermal cycling：group A（0.36 ± 0.01）mm，group B（0.37 ± 0.01）mm，group C（0.38 ± 0.02）mm. There was no statistically significant difference in dye penetration depth of the axial wall and the gingival wall among the three groups of specimens（P > 0.05）. Conclusion    Under the existing conditions of this experiment，considering the fracture resistance and the marginal adaptation，Lava Ultimate is more suitable for inlay restoration of primary teeth than the other two materials.

Key words: primary teeth, tooth defect, inlay, fracture resistance, marginal adaptation

摘要： 摘要：目的    评估不同材料嵌体修复离体乳磨牙的断裂载荷及边缘密合性。方法    收集2020年7月至2021年7月于第四军医大学口腔医院儿童口腔科新鲜拔除的牙冠完整且根吸收不超过2/3的下颌第二乳磨牙55颗，用丙烯酸树脂块制备成试件。随机选择10个试件作为对照组；其余试件完成Ⅱ类洞嵌体预备后随机分为3组（每组15个），分别使用3种不同材料完成嵌体修复（A组：IPS e. max CAD；B组：Lava Ultimate；C组：BioPAEK）。检测各组修复后即刻断裂载荷、冷热循环后断裂载荷、冷热循环后边缘密合性，并进行比较分析。结果    修复后即刻4组试件断裂载荷分别为A组（1527 ± 21.06）N、B组（1616 ± 23.85）N、C组（1580 ± 19.63）N、对照组（1643 ± 19.60）N，其中A组和C组断裂载荷均明显小于对照组断裂载荷（P < 0.05），B组断裂载荷与对照组断裂载荷差异无统计学意义（P > 0.05），B组和C组断裂载荷均明显大于A组断裂载荷（P < 0.05）。冷热循环后4组试件断裂载荷分别为A组（1477 ± 29.44）N、B组（1567 ± 24.17）N、C组（1484 ± 23.33）N、对照组（1608 ± 26.45）N，其中B组断裂载荷明显高于A组和C组（P < 0.05），与对照组差异无统计学意义（P > 0.05）。冷热循环后3组试件轴壁染料渗透深度：A组（0.20 ± 0.02）mm、B组（0.21 ± 0.01）mm、C组（0.20 ± 0.02）mm；龈壁染料渗透深度：A组（0.36 ± 0.01）mm、B组（0.37 ± 0.01）mm、C组（0.38 ± 0.02）mm。3组试件轴壁及龈壁染料渗透深度差异均无统计学意义（P > 0.05）。结论    本实验现有条件下，综合考虑断裂载荷及边缘密合性，Lava Ultimate较其他两种材料更适用于乳牙的嵌体修复。

关键词: 乳牙, 牙体缺损, 嵌体, 断裂载荷, 边缘密合性