Rippe Marília Pivetta, Santini Manuela Favarin, Bier Carlos Alexandre Souza, Borges Alexandre Luiz Souto, Valandro Luiz Felipe
Department of Dental Materials and Prosthodontics, São José dos Campos School of Dentistry, UNESP - Univ Estadual Paulista, São José dos CamposSP, Brazil.
Department of Stomatology, School of Dentistry, UFSM - Federal University of Santa Maria, Santa MariaRS, Brazil.
Braz Dent J. 2013 Nov-Dec;24(6):619-25. doi: 10.1590/0103-6440201301996.
The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth.
本研究的目的是评估根管充填技术对牙根抗折性的影响，并通过有限元分析（FEA）分析两种不同根管技术中根管封闭剂的膨胀情况。选取30颗单根人牙，用旋转锉将其预备至标准化工作长度14 mm。使用塑料圆柱体作为模具将标本嵌入丙烯酸树脂中，并分为3组（n = 10）：G（侧方加压）组 - 侧方加压法；G（单锥法）组 - 单锥法；G（塔格法）组 - 塔格混合技术。使用锥形玻璃纤维增强复合桩系统的#3预备钻将根管预备至11 mm长度。所有牙根均植入玻璃纤维桩，用粘结剂粘结，并制作复合树脂核。所有组均进行抗折强度测试（1 mm/min，45°）。数据采用单因素方差分析进行统计学分析，显著性水平为5%。使用两种模型进行有限元分析：一种模拟侧方加压法和塔格混合技术，另一种模拟单锥法。第二个模型设计的牙胶量比第一个模型小两倍，封闭剂层比第一个模型厚两倍。结果采用冯·米塞斯应力准则进行分析。单因素方差分析表明，根管充填技术影响抗折强度（p = 0.004）。G（侧方加压）组和G（塔格法）组产生的抗折强度值相似，而G（单锥法）组显示出最低值。有限元分析表明，单锥模型在根管壁上产生更高应力。封闭剂厚度似乎影响根管治疗后修复牙的抗折强度。
