do Valle Accácio Lins, Pereira Jefferson Ricardo, Shiratori Fábio Kenji, Pegoraro Luiz Fernando, Bonfante Gerson
Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo.
J Appl Oral Sci. 2007 Feb;15(1):29-32. doi: 10.1590/s1678-77572007000100007.
This study evaluated the fracture strengths of endodontically treated teeth restored with prefabricated posts with different post lengths.
Thirty freshly extracted canines were endodontically treated. They were randomly divided into groups of 10 teeth and prepared according to 3 experimental protocols, as follows; Group 1/3 PP: teeth restored with prefabricated post and composite resin core (Z250) with post length of 5.0mm; Group 1/2 PP and Group 2/3 PP: teeth restored with prefabricated post and composite resin core (Z250) with different combinations of post length of 7.5mm and 10mm, respectively. All teeth were restored with full metal crowns. The fracture resistance (N) was measured in a universal testing machine (crosshead speed 0.5mm/min) at 45 degrees to the tooth long axis until failure. Data were analyzed by one-way analysis of variance (alpha=.05).
The one-way analysis of variance demonstrated no significant difference among the different post lengths (P>.05) (Groups 1/3 PP = 405.4 N, 1/2 PP = 395.6 N, 2/3 PP = 393.8 N). Failures occurred mainly due to core fracture.
The results of this study showed that an increased post length in teeth restored with prefabricated posts did not significantly increase the fracture resistance of endodontically treated teeth.
本研究评估了用不同桩长度的预制桩修复的根管治疗后牙齿的抗折强度。
30颗新鲜拔除的犬牙进行根管治疗。将它们随机分为每组10颗牙的组，并根据以下3种实验方案进行制备；第1/3组PP：用桩长度为5.0mm的预制桩和复合树脂核（Z250）修复的牙齿；第1/2组PP和第2/3组PP：分别用桩长度为7.5mm和10mm的不同组合的预制桩和复合树脂核（Z250）修复的牙齿。所有牙齿均用全金属冠修复。在万能试验机（十字头速度0.5mm/min）中以与牙长轴成45度角测量抗折强度（N），直至失效。数据采用单因素方差分析（α = 0.05）进行分析。
单因素方差分析表明不同桩长度之间无显著差异（P>0.05）（第1/3组PP = 405.4 N，第1/2组PP = 395.6 N，第2/3组PP = 393.8 N）。失败主要是由于核折裂。
本研究结果表明，用预制桩修复的牙齿中增加桩长度并未显著提高根管治疗后牙齿的抗折强度。
