Martelli H, Pellizzer E P, Rosa B T, Lopes M B, Gonini A
University North of Paraná, Londrina, Paraná, Brazil.
Int Endod J. 2008 Aug;41(8):685-92. doi: 10.1111/j.1365-2591.2008.01424.x. Epub 2008 Jun 28.
To evaluate the mechanical behaviour of structurally compromised root filled bovine roots after restoration with accessory glass fibre posts.
Fifty roots of bovine teeth received conventional post preparations with a cervical diameter of 3.5 mm. The roots were assigned to five groups (n = 10): group MP - cast metal post, group GP - glass fibre post and group AGP - glass fibre post plus accessory glass fibre posts. In groups GP-R and AGP-R (similar to groups GP and AGP), 2 mm of coronal tooth structure were left intact. All groups were subjected to an elastic limit assay and tested in an universal machine for fracture resistance. Repeated measures anova were performed to examine differences in fracture resistance; fracture modes were analysed by Fischer's exact test.
The mean fracture resistance values (kgf) were 61.8 (MP), 63.1 (GP), 55.5 (AGP), 56 (GP-R) and (53.1) AGP-R. No statistically significant difference was found between groups. The Fisher's exact test indicated significant differences (P < 0.05) in the fracture mode amongst groups MP, GP and AGP, indicating 100%, 50% and 10% of catastrophic fractures, respectively.
The use of accessory glass fibre posts affected the fracture mode favorably: 90% of fractures in group AGP were in the coronal third.
评估使用辅助玻璃纤维桩修复后结构受损的根管充填牛牙根的力学行为。
五十颗牛牙牙根进行常规桩道预备，颈部直径为3.5毫米。将牙根分为五组（n = 10）：MP组 - 铸造金属桩，GP组 - 玻璃纤维桩，AGP组 - 玻璃纤维桩加辅助玻璃纤维桩。在GP-R组和AGP-R组（类似于GP组和AGP组）中，保留2毫米的冠部牙体结构完整。所有组均进行弹性极限测定，并在万能试验机上测试抗折强度。采用重复测量方差分析来检验抗折强度的差异；通过Fisher精确检验分析折裂模式。
平均抗折强度值（kgf）分别为61.8（MP）、63.1（GP）、55.5（AGP）、56（GP-R）和53.1（AGP-R）。各组之间未发现统计学上的显著差异。Fisher精确检验表明，MP组、GP组和AGP组之间的折裂模式存在显著差异（P < 0.05），分别表明灾难性折裂的比例为100%、50%和10%。
使用辅助玻璃纤维桩对折裂模式有有利影响：AGP组中90%的折裂发生在冠部三分之一处。
