【摘要】 目的:探讨上颌前磨牙桩道预备后剩余根管壁厚度及对抗折强度的影响。方法:对100颗单、双根管上颌 前磨牙,用1#～5#P型钻进行桩道预备,用光学显微镜分别测量各组牙冠方和根方剩余根管壁厚度,并观察桩道预 备对抗折强度的影响。结果:单根管上颌前磨牙,1#～2#P型钻预备后,各壁剩余厚度均大于1mm;而对于双根管 上颌前磨牙,1#～3#P型钻预备后,各壁剩余厚度均大于1mm。另外,1#～5#P型钻预备后,牙根抗折强度逐渐变小 (P 0.01),且相同直径器械预备后,双根管抗折强度大于单根管(P 0.01)。结论:用P型钻预备桩道时,单根 管牙最大可用2#P型钻预备,双根管牙最大可用3#P型钻预备,且剩余牙质的量与牙齿的抗折强度成正相关。更多还原

【Abstract】 Objective: To investigate the residual thickness in maxillary premolars after space preparation and the influence of post space preparation on fracture strength. Methods: Post preparation was made in 100 maxillary premolars with one and two root canals with 1 #~5 # peeso drills .The root thickness of both the coronal and the apical sections was measured with binocular microscope and find out the influence of post preparations on fracture strength. Results: In single-canal maxillary premolars ,the diameter of peeso drills that preserved a minimnm of 1mm wall thickness was 1 #~2 # ;whereas for two-canal teeth ,the type was 1 #~3 # .In addition ,the fracture strength got weaker and weaker after post preparations with 1 #~5 # peeso drills(P<0.01) .At the same time ,prepare post with same diameter instrument ,the fracture strength was stronger in two-canal teeth than in single-canal teeth(P<0.01). Conclusion: In single-canal maxillary premolars ,the maximnm diameter of peeso drill was 1# to prepare post ,whereas for two-canal teeth ,the type was 3# .After post preparation ,fracture strength was directly proportional to residual thickness of root.更多还原