不同桩核系统修复上颌前磨牙双根管的抗折力研究

Fracture resistance of two root canals of maxillary first premolars restored with different post-core systems

目的比较不同桩核系统修复上颌前磨牙双根管的抗折强度。方法将36颗因正畸拔除的上颌第一前磨牙,沿釉牙本质界冠方2mm水平切除牙冠,常规根管治疗后随机分为A、B、C三组,A组给予铸造镍铬合金桩核+金属全冠;B组给予MACROLOCKT石英纤维桩+树脂核+金属全冠,C组给予TENAX玻璃纤维桩+树脂核+金属全冠修复。应用力学试验机进行抗力性检测,记录试件破坏时施力的大小,观察试件破坏的形式及部位。结果 A组、B组、C组的离体牙桩核冠修复后牙体折断时的最大载荷分别为(1059.11±123.54)N、(1075.17±64.37)N、(1341.81±128.11)N。三组抗折强度两两比较,没有显著性差异(P>0.05)。A组不可复性折断明显多于B组和C组,差异有统计学意义(P<0.05),B组与C组的抗折强度、破坏性折断例数比较,差异无统计学意义(P>0.05)。结论采用不同桩核系统修复上颌前磨牙双根管的抗折强度无明显差异。玻璃纤维桩与石英纤维桩极大降低了根折率,有利于此类根管的保留和再修复。

Objective To compare the fracture resistance and the mode of failure of endodontically treated maxillary first premolar with different post-core systems. Methods Thirty-six maxillary first premolars extracted for orthodontic treatment were selected. The crowns were sectioned at 2mm above the labial cementoenamel junction （CEJ）. Then they were endodontically treated. The prepared teeth were randomly divided into three groups. Group A was restored with cast Ni-Cr post-core and mental crown, Group B with quartz fiber post combined with resin core and mental crown, Group C with glass fiber post combined with resin core and mental crown. All samples were tested on the universal test machine. The fracture resistance strength was measured and the data were statistically analyzed. Results The maximum load at fracture of the A, B and C groups was （1059. 11±123.54）N, （1075.17±64. 37）N and （1341.81±128. 11 ）N, respectively. There was no significant difference in the load among the three groups （ P〉0.05 ）. But, there was more irreducible fracture in group A than in group B and C （ P 〈 0.05）. No difference in fracture resistance and destructive fracture was found between group B and group C （ P 〉 0. 05）. Conclusion The fracture resistance strength of two root canals of maxillary first premolars restored with different post core systems had no significant difference. Teeth restored with the glass fiber post and quartz fiber post showed the most favorable fracture modes.