Marchionatti Ana Maria Estivalete, Wandscher Vinícius Felipe, Broch Juliana, Bergoli César Dalmolin, Maier Juliana, Valandro Luiz Felipe, Kaizer Osvaldo Bazzan
Department of Restorative Dentistry, School of Dentistry, Federal University of Santa Maria, Santa Maria, RS, Brazil.
Department of Restorative Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.
J Appl Oral Sci. 2014 Sep-Oct;22(5):450-8. doi: 10.1590/1678-775720140067.
Considering that periodontal ligament simulation may influence the stress distribution over teeth restored with intraradicular retainers, this study aimed to assess the combined effect of mechanical cycling and periodontal ligament simulation on both the bond strength between fiber posts and root dentin and the fracture resistance of teeth restored using glass fiber posts.
Ninety roots were randomly distributed into 3 groups (n=10) (C-MC: control; P-MC: polyether; AS-MC: addition silicone) to test bond strength and 6 groups (n=10) (C: control; P: polyether; AS: addition silicone, without mechanical cycling, and C-MC, P-MC and AS-MC with mechanical cycling) to test fracture strength, according to the material used to simulate the periodontal ligament. For the bond strength test, fiber posts were cemented, cores were built, mechanical cycling was applied (2×10(6) cycles, 88 N, 2.2 Hz, and 45º incline), and the teeth cut into 3 slices (2 mm), which were then subjected to the push-out test at 1 mm/min. For the fracture strength test, fiber posts were cemented, cores were built, and half of the groups received mechanical cycling, followed by the compressive strength (45° to the long axis and 1 mm/min) performed on all groups.
Periodontal ligament simulation did not affect the bond strength (p=0.244) between post and dentin. Simulation of periodontal ligament (p=0.153) and application of mechanical cycling (p=0.97) did not affect fracture resistance.
The materials used to simulate the periodontal ligament did not affect fracture or bond strength, therefore periodontal ligament simulation using the tested materials could be considered optional in the conditions of the study.
鉴于牙周膜模拟可能会影响使用根管内固位体修复的牙齿的应力分布，本研究旨在评估机械循环和牙周膜模拟对纤维桩与牙根牙本质之间的粘结强度以及使用玻璃纤维桩修复的牙齿的抗折强度的综合影响。
根据用于模拟牙周膜的材料，将90颗牙根随机分为3组（n = 10）（C-MC：对照组；P-MC：聚醚组；AS-MC：加成型硅橡胶组）以测试粘结强度，以及6组（n = 10）（C：对照组；P：聚醚组；AS：加成型硅橡胶组，无机械循环，以及C-MC、P-MC和AS-MC有机械循环）以测试抗折强度。对于粘结强度测试，粘结纤维桩，制作核，施加机械循环（2×10⁶次循环，88 N，2.2 Hz，45°倾斜），然后将牙齿切成3片（2 mm），接着以1 mm/min的速度进行推出试验。对于抗折强度测试，粘结纤维桩，制作核，一半的组接受机械循环，然后对所有组进行抗压强度测试（与长轴成45°，1 mm/min）。
牙周膜模拟不影响桩与牙本质之间的粘结强度（p = 0.244）。牙周膜模拟（p = 0.153）和机械循环的应用（p = 0.97）不影响抗折强度。
用于模拟牙周膜的材料不影响抗折或粘结强度，因此在本研究条件下，使用测试材料进行牙周膜模拟可被视为非必需。
