根管治疗术后不同修复方式对牙根抗折性能的影响

Effects of different restoration methods on fracture resistance of endodontically treated teeth

目的研究根管治疗后不同修复方式对牙齿抗折性能的影响。方法将50颗同名离体牙随机分为五个组:对照组(A组)为完整离体牙,实验组(B-E组)制备根管治疗及邻牙合面缺损洞型模型。四个实验组分别选用不同的处理方式:不修复缺损、树脂直接充填修复、树脂嵌体间接修复、树脂直接充填+固位纤维冠外保护。模拟口内咀嚼力,采用加载速度为1.00 mm/min匀速加载于与牙体长轴呈45°颊尖舌斜面中点,对比分析各组试样的破坏载荷。结果根管治疗后未修复患牙的破坏载荷(0.23±0.17kN)远低于完整离体牙(1.27±0.41 kN)(P<0.05)。树脂直接充填修复后,患牙的破坏载荷为0.55±0.31 kN,抗折性能仍难以达到完整离体牙水平(P<0.05);树脂嵌体间接修复或树脂直接充填+固位纤维冠外保护后,患牙的破坏载荷分别为0.89±0.40 kN和0.98±0.34 kN,抗折性能可以达到完整离体牙水平(P>0.05)。结论根管治疗后患牙抗折性能降低,嵌体修复及树脂充填+固位纤维冠外保护两种方法可明显提高牙齿抗折性能。

Objective To evaluate the effect of different restoration methods on fracture resistance of endodontically treated teeth. Methods Fifty intact extracted maxillary first premolars were randomly divided into 5 groups. Medial-occlusal cavity models were established in all the test groups （B-E） according to the same standard, followed by treatments with defect exposure only, defect filling with light cured composite resin, indirect resin inlays, or light cured composite resin combined with Biosplint tiber. Each specimen was tested using a universal test machine at 1.00 mm/min until fracture and the fracture load was recorded. The load angle was 45 degree to the long axis of the teeth, and the load was pointed to the middle of the lingual surface on the buccal cusp. The fracture resistance was analyzed statistically. Results The mean load to cause fracture of the samples in each group group A to E was 1.27±0.41, 0.23±0.17, 0.55±0.31, 0.89±0.40, and 0.98±0.34 kN, respectively, showing significant differences between the groups. Conclusion The fracture resistance of the teeth is reduced after endodontic therapy, but can be increased significantly by restoration with composite resin inlay or light cured composite resin combined with Biosplint fiber.