Institute of Oral Medicine, Department of Stomatology, National Cheng Kung University College of Medicine and Hospital, Tainan, Taiwan.
J Prosthet Dent. 2010 Dec;104(6):379-88. doi: 10.1016/S0022-3913(10)60171-0.
Cast posts require sufficient length for prosthesis retention and root strength. For prefabricated metal and fiber posts, the effects of different post lengths on the strength and internal stress of the surrounding root need evaluation.
The purpose of this study was to examine, using both experimental and finite element (FE) approaches, the influence of post material and length on the mechanical response of endodontically treated teeth.
Sixty extracted incisors were endodontically treated and then restored with 1 of 3 prefabricated posts: stainless steel (SS), carbon fiber (CF), and glass fiber (GF), with intraradicular lengths of either 5 or 10 mm (n=10). After composite resin core and crown restorations, these teeth were thermal cycled and then loaded to fracture in an oblique direction. Statistical analysis was performed for the effects of post material and length on failure loads using 2-way ANOVA (α=.05). In addition, corresponding FE models of an incisor restored with a post were developed to examine mechanical responses. The simulated tooth was loaded with a 100-N oblique force to analyze the stress in the root dentin.
The SS/5 mm and all fiber post groups presented no statistical differences, with mean (SD) fracture loads of 1247 to 1339 (53 to 121) N. The SS/10 mm group exhibited a lower fracture load, 973 (115) N, and a higher incidence of unfavorable root fracture (P<.05). The FE analysis showed high stress around the apical end of the long SS post, while stress was concentrated around the crown margins in the fiber post groups.
Both long and short fiber posts provided root fracture resistance comparable to that of SS posts. For metal posts, extending the post length does not effectively prevent root fracture in restored teeth.
铸造桩需要足够的长度来保持修复体的固位力和牙根强度。对于预制金属和纤维桩，需要评估不同桩长度对牙根强度和内部应力的影响。
本研究旨在通过实验和有限元（FE）方法，研究桩材料和长度对根管治疗牙力学性能的影响。
60 颗离体切牙进行根管治疗，然后用 3 种预制桩中的 1 种修复：不锈钢（SS）、碳纤维（CF）和玻璃纤维（GF），根内长度分别为 5 或 10mm（n=10）。复合树脂核和冠修复后，这些牙齿进行热循环，然后以倾斜方向加载至断裂。使用 2 因素方差分析（α=.05）对桩材料和长度对失效载荷的影响进行统计分析。此外，还开发了相应的带桩修复的切牙 FE 模型，以研究力学响应。模拟牙用 100N 的倾斜力加载，分析牙根牙本质的应力。
SS/5mm 和所有纤维桩组之间没有统计学差异，平均（SD）断裂载荷为 1247 至 1339（53 至 121）N。SS/10mm 组的断裂载荷较低，为 973（115）N，且根部骨折的发生率较高（P<.05）。FE 分析显示，长 SS 桩根尖端周围的应力较高，而纤维桩组的应力集中在冠缘周围。
长、短纤维桩提供的牙根抗折能力与 SS 桩相当。对于金属桩，延长桩的长度并不能有效地防止修复牙的根折。
