Amaral M, Favarin Santini M, Wandscher V, Villaça Zogheib L, Valandro L F
Oral Science, School of Dentistry, Department of Restorative Dentistry, Division of Prosthodontics, Federal University of Santa Maria, Santa Maria, Brazil.
Minerva Stomatol. 2009 Mar;58(3):99-106.
The aim of this study was to evaluate fracture resistance of bovine teeth restored with glass fiber posts of different diameter and shape.
Eighty single-rooted bovine teeth were prepared, embedded in a PVC cylinder using acrylic resin, and allocated into eight groups (N.=10) based on the post diameter (White Post DC) and shape: smooth double-tapered fiber post -- G1, G2, G3, and G4 with cervical diameters of 1.4 mm, 1.6 mm, 1.8 mm, and 2 mm, respectively; double-tapered fiber post with coronal macroretentions -- G5, G6, G7, and G8 with cervical diameters of 1.4 mm, 1.6 mm, 1.8 mm, and 2 mm, respectively. A three-step etch-and.rinse adhesive and resin cement system was used for postcementation. Afterwards, the core build-up was standardized with composite resin (Oppalis). The specimens were stored for seven days and later submitted to monotonic load at a crosshead speed of 0.05 cm/min (45 degrees ) until failure. The fracture loads were determined and the fracture mode was recorded.
The post diameter (P=0.0007) and post-surface characteristic (P=0.0149) factors affected the fracture resistance results significantly (2-way ANOVA). Low fracture strength values were noted in the group with narrower diameter and macroretentions (G5). The macroretentions damaged the fracture resistance results when post diameter was 1.4 mm (G1 and G5). On fiber posts having diameters of 1.6 mm, 1.8 mm, and 2 mm, macroretentions did not impair fracture strengths significantly.
A direct relation between the diameter of the fiber post and the fracture strength seems likely. Coronal macroretentions reduced fracture strength in thinner fiber posts.
本研究旨在评估用不同直径和形状的玻璃纤维桩修复的牛牙的抗折性能。
制备80颗单根牛牙，用丙烯酸树脂嵌入PVC圆柱体中，并根据桩的直径（白色桩DC）和形状分为八组（每组n = 10）：光滑双锥纤维桩——G1、G2、G3和G4，其颈部直径分别为1.4mm、1.6mm、1.8mm和2mm；带冠部大固位形的双锥纤维桩——G5、G6、G7和G8，其颈部直径分别为1.4mm、1.6mm、1.8mm和2mm。采用三步酸蚀冲洗粘结剂和树脂水门汀系统进行桩粘结。之后，用复合树脂（Oppalis）进行核修复标准化。将标本储存7天，然后以0.05cm/min（45度）的十字头速度进行单调加载直至破坏。测定抗折载荷并记录骨折模式。
桩直径（P = 0.0007）和桩表面特征（P = 0.0149）因素对抗折性能结果有显著影响（双向方差分析）。在直径较窄且有大固位形的组（G5）中观察到较低的抗折强度值。当桩直径为1.4mm时（G1和G5），大固位形会损害抗折性能结果。在直径为1.6mm、1.8mm和2mm的纤维桩上，大固位形对抗折强度没有显著损害。
纤维桩直径与抗折强度之间似乎存在直接关系。冠部大固位形会降低较细纤维桩的抗折强度。
