Int J Prosthodont. 2020 May/Jun;33(3):321-327. doi: 10.11607/ijp.6423.
To assess the influence of ferrule thickness on the fracture resistance and failure mode of endodontically treated bovine incisors and to predict the long-term prognosis, as well as choose the most suitable clinical treatment, for teeth with different ferrule thicknesses.
A total of 50 endodontically treated bovine incisors were restored with quartz fiber posts and metal crowns and separated into five groups (n = 10 each): no ferrule (group A); 0.5-mm-thick ferrule (group B); 1.0-mm-thick ferrule (group C); 1.5-mm-thick ferrule (group D); and 2.0-mm-thick ferrule (group E). All specimens were subjected to a fatigue loading test (2.33 Hz, 50 N, 300,000 cycles). Survived specimens were loaded until fracture on a universal testing machine at an angle of 135 degrees and a crosshead speed of 0.5 mm/minute. Failure modes and fracture resistance were recorded. Data were analyzed using one-way ANOVA and least significant difference tests.
A significant increase (P < .05) was detected in fracture resistance with increase in ferrule thickness. Group D (1.5 mm) and group E (2.0 mm) showed significantly higher fracture resistance than the other three groups. All failures belonged to restorable fracture patterns.
Ferrule thickness contributed significantly to the fracture resistance of endodontically treated bovine incisors restored with quartz fiber posts and metal crowns. Teeth with ferrule thickness of ≥ 1.5 mm can achieve higher fracture resistance and have a better long-term prognosis.
评估不同牙体预备肩台厚度对根管治疗后牛切牙抗折性能和破坏模式的影响，并预测不同肩台厚度牙体的长期预后，从而选择最合适的临床治疗方案。
共 50 颗根管治疗后的牛切牙被修复为石英纤维桩和金属冠，并分为 5 组（每组 n = 10）：无肩台（A 组）；0.5mm 肩台（B 组）；1.0mm 肩台（C 组）；1.5mm 肩台（D 组）；2.0mm 肩台（E 组）。所有标本均进行疲劳加载试验（2.33Hz，50N，300000 次）。存活标本在万能试验机上以 135 度和 0.5mm/min 的十字头速度加载至断裂。记录破坏模式和抗折性能。采用单因素方差分析和最小显著差异检验对数据进行分析。
牙体预备肩台厚度的增加显著提高了抗折性能（P <.05）。D 组（1.5mm）和 E 组（2.0mm）的抗折性能显著高于其他三组。所有的破坏均属于可修复的断裂模式。
牙体预备肩台厚度对石英纤维桩和金属冠修复的根管治疗后牛切牙的抗折性能有显著影响。肩台厚度≥1.5mm 的牙齿可以获得更高的抗折性能和更好的长期预后。
