可塑纤维桩修复对根管治疗牙抗折强度的影响

Fracture resistance and failure modes of endodontically treated human teeth restored with four different post-core systems

目的比较不同桩修复离体牙对修复体整体抗折强度的影响。方法将32颗上颌前磨牙行根管治疗并从唇侧釉牙骨质界上2mm处截断后随机分为4组,A组采用镍铬金属铸造桩核加铸造冠修复,B组采用Tenax Fiber White纤维桩、树脂核加铸造冠修复,C组采用EverStick可塑纤维桩单根(直径1.5mm)、树脂核加铸造冠修复,D组采用EverStick可塑纤维桩双根(直径1.5mm和1.2mm)、树脂核加铸造冠修复。所有离体牙均由自凝树脂包埋,电子万能试验机加载头与牙体长轴成45°,以1mm/min的加载速度加载直至试件任何部分折裂,记录读数并观察修复体折裂模式。结果A、B、C、D组间修复体的整体抗折强度差异无统计学意义(P>0.05)。各纤维桩组牙体折裂位置较铸造桩更接近牙颈部。结论尽管可塑纤维桩自身的弯曲强度较低,但是修复离体牙后整体抗折强度较高,可以满足临床要求。各纤维桩组折裂模式较铸造桩组更有利于修复体失败后的再修复。

Objective To compare the fracture resistance and failure modes of endodontically treated human upper premolars restored with different post-core systems. Methods 32 extracted human upper premolars were endodontically treated and crowns were sectioned at 2 mm above the labial cement enamel junction （CEJ）. The teeth were randomly and equally divided into 4 groups： Group A, teeth restored with cast metal post and metal crown; group B, Tenax Fiber White fiber post and metal crown; group C, EverStick fiber post 1.5 mm in diameter and metal crown; group D, EverStick fiber post 1.5 mm in diameter and add another 1.2 mm diameter EverStick fiber post and metal crown. All the teeth were embedded in acrylic resin blocks, and were subjected to a compressive load at 1 mm/min crosshead speed which delivered at a 45° to the long axis until the first sign of failure was noted. The fracture load and the mode of fracture were recorded. Results Fracture resistances of the four groups of restored teeth were not significantly different （P〉0.05）. However, fracture modes in fiber post groups were nearer to CEJ than cast metal post group. Conclusion Fracture resistance of endodontically treated teeth restored with Ever- Stick fiber post is enhanced that it can meet the clinical need, although the flexural resistance of EverStick fiber post itself is the weakest. Fracture modes of all fiber post groups are more favorable than cast metal post group.