不同修复方法对邻[牙合]缺损的下颌前磨牙根管治疗术后抗折性能影响的研究

目的：比较不同修复方法对邻牙合]缺损的下颌前磨牙根管治疗术后抗折强度的影响。方法：将50颗离体下颌前磨牙随机分为A、B、C、D、E五组，每组10颗。A组（对照组）：完整离体牙，不做任何处理。其它四组（实验组）样本牙经根管治疗并制备邻骀缺损。B组：光固化树脂直接充填；C组：树脂充填＋铸造全冠修复；D组：铸造桩核＋铸造全冠修复；E组：纤维桩树脂核＋铸造全冠修复。所有样本牙在电子万能试验机上以与牙体长轴成30°角、lmm／min速度加载直至样本折裂，记录样本折裂时的载荷数值与折裂模式，对数据进行统计分析。结果：A、B、C、D、E组的折裂载荷分别为（952．93±102．03）、（383．97±46．31）、（733．51±54．94）、（604．76±123．73）和（893．44±87．08）N。五组之间两两比较，只有A、E两组之间差异无统计学意义，其余差异均有统计学意义；A、B、C、D、E组产生不可修复性折裂（根折位于包埋树脂平面以下）的样本数分别为0、2、1、9、3，其中D组牙体的折裂模式与其它三组差异均存在统计学意义，剩余三组间两两比较差异无统计学意义。结论：纤维桩树脂核联合全冠修复可作为邻牙合]缺损的前磨牙根管治疗术后的优选修复方式。

Fracture resistance of restorations of endodontically treated mandibular premolars with proximal-occlnsal defects

Objective： To compare the fracture resistance of endodontically treated premolars with proximal-occlusal defects with different restorations. Methods： Fifty recently extracted intact mandibular premolars were randomly divided into five groups （n= 10）. Group A （control group）： intact teeth without any treatments. Other groups were prepared of proximal-oc- clusal defects followed by RCT. Group B： filled with a light-curing composite resin. Group C： restored with light-curing composite resin filling and cast full crowns. Group D： restored with cast post-cores and crowns. Group E： restored with fiber posts and resin cores and cast full crowns. All specimens were loaded in a universal testing machine at a speed of 1.0mm/min with an angle of 30 degrees to the long angle of the teeth. Fracture loads and models were recorded and ana： lyzed statistically. Results： Mean fracture loads of five groups were as follows, respectively. Group A： 952.93±102.03N, group B： 383.97± 46.31N, group C： 733.51± 54.94N, group D： 604.76± 123.73N, group E： 893.44±87.08N. There was no significant difference between group A and group E. The rest were statistically significant. The number of unrepairable fracture （under the embedding resin plane） in group A, B, C, D, E were 0, 2, 1, 9, 3, respectively. The differences were statistically significant between group D and the other groups. There was no significant difference among B, C, E groups. Conclusion： Fiber posts and resin cores combined with full crown could be used as the first choice to restore endodontically treated premolars with proximal-occlusal defects.