Ananviriyaporn Sirirat, Jitarmat Piyabhorn, Chairat Surachara, Ranchan Atchariyaporn
Department of Prosthodontics, Faculty of Dentistry, Thammasart University, Pathumthani, Thailand.
J Med Assoc Thai. 2012 Jan;95 Suppl 1:S115-9.
Endodontically treated teeth often have a varying remaining coronal tooth structure, is an important factor in the successful of post-core with crown restoration.
This study compared the fracture resistance of pulpless teeth with variable amounts of remaining coronal tooth structure restored with fiber-reinforced composite posts and composite core.
Fifty extracted human premolars were endodontically treated and divided into 5 groups of 10 teeth each. Four groups were prepared having axial wall heights of 4 mm around the preparation circumferences. In 3 of the groups with axial tooth structure, mesial axial tooth structure was removed, mesial and lingual axial tooth structure were removed, mesial-lingual and distal axial tooth structure were removed. For the fifth group, all axial tooth structure was removed to the level of the prepared finish line. All 50 prepared teeth were restored with fiber-reinforced composite posts (FRC Postec Plus) and composite resin cores (Multicore Flow). Testing was conducted with a universal testing machine with the application of a static load to the lingual incline plane of buccal cusp at a crosshead speed of 5 mm/min at 45 degrees to the long axis of the tooth. The load at failure was recorded. The data were subjected to 1-way analysis of variance.
The mean value + standard deviation for the failure load of group 1 to 5 were 237.48 +/- 81.87, 242.97 +/- 66.80, 257.67 +/- 70.42, 239.56 +/- 70.42 and 297.70 +/- 99.42 (N), respectively There were no significant differences in the fracture resistance (p < 0.01). No root fractures occurred in any of the groups.
The varying remaining coronal tooth structure of endodontically treated tooth had no influenced on the fracture resistance when restored with fiber-reinforced composite posts and composite core.
根管治疗后的牙齿通常剩余不同的冠部牙体结构，这是桩核冠修复成功的一个重要因素。
本研究比较了用纤维增强复合树脂桩和复合树脂核修复的剩余不同冠部牙体结构的无髓牙的抗折性能。
选取50颗拔除的人前磨牙进行根管治疗，分为5组，每组10颗牙。4组制备的牙体在制备圆周周围的轴向壁高度为4mm。在3组有轴向牙体结构的牙齿中，分别去除近中轴向牙体结构、近中和舌侧轴向牙体结构、近中舌侧和远中轴向牙体结构。对于第5组，将所有轴向牙体结构去除至制备完成线水平。所有50颗制备好的牙齿均用纤维增强复合树脂桩（FRC Postec Plus）和复合树脂核（Multicore Flow）进行修复。使用万能试验机进行测试，以5mm/min的十字头速度在与牙长轴呈45度角的颊尖舌侧斜面上施加静态载荷。记录破坏时的载荷。数据进行单因素方差分析。
第1组至第5组破坏载荷的平均值±标准差分别为237.48±81.87、242.97±66.80、257.67±70.42、239.56±70.42和297.70±99.42（N）。抗折性能无显著差异（p<0.01）。所有组均未发生牙根折断。
根管治疗后牙齿剩余不同的冠部牙体结构在用纤维增强复合树脂桩和复合树脂核修复时对抗折性能无影响。
