Amarnath G S, Swetha M U, Muddugangadhar B C, Sonika Radhika, Garg Ashu, Rao T R Poonam
Head, Department of Prosthodontics including Crown and Bridge and Implantology, M R Ambedkar Dental College and Hospital, Bengaluru, Karnataka, India.
Private Practitioner, Bengaluru, Karnataka, India.
J Int Oral Health. 2015 Jul;7(7):22-8.
Endodontically treated teeth with posts are more prone to fracture. Hence, the purpose of this study was to investigate the in-vitro fracture resistance of devitalized teeth and mode of failure restored with posts of different materials and different lengths.
Sixty freshly extracted human mandibular premolars were endodontically treated and then restored with 1 of 2 prefabricated posts: Stainless-steel (SS) and glass-fiber (fiber posts [FP]) with intraradicular lengths of 4, 5 or 10 mm (n = 10). Following core restoration, a static compressive load was applied perpendicular to the long-axis of the teeth. Initial failure of each specimen was recorded in Newton. The mode of failure was also determined radiographically. The data were analyzed using two-way ANOVA and Tukey's post-hoc analysis with Bonferroni adjustment.
Analysis indicated significant differences (P < 0.001) among the groups. Among the SS posts, SS/7 (246 N) exhibited the highest failure load and SS/4 (122 N) the lowest. FP/10 (140.5 N) exhibited the highest failure load among the FP and FP/4 (68.5 N) the lowest. SS posts showed post pull out, followed by core fracture while FP showed core debonding, followed by core fracture as the primary mode of failure.
Fracture resistance of the teeth proportionately increased with increase in the length of FP while it decreased with that of metal post. SS posts showed greater fracture resistance than FP when 90° load was applied.
根管治疗后带桩的牙齿更容易发生折断。因此，本研究的目的是调查失活牙用不同材料和不同长度桩修复后的体外抗折性及失败模式。
60颗新鲜拔除的人下颌前磨牙进行根管治疗，然后用两种预制桩中的一种进行修复：不锈钢（SS）桩和玻璃纤维桩（纤维桩[FP]），根管内长度分别为4mm、5mm或10mm（n = 10）。进行核修复后，垂直于牙齿长轴施加静态压缩载荷。记录每个样本的初始破坏载荷，单位为牛顿。还通过影像学确定失败模式。使用双向方差分析和经Bonferroni校正的Tukey事后分析对数据进行分析。
分析表明各组之间存在显著差异（P < 0.001）。在不锈钢桩组中，SS/7（246N）的破坏载荷最高，SS/4（122N）最低。在纤维桩组中，FP/10（140.5N）的破坏载荷最高，FP/4（68.5N）最低。不锈钢桩的主要失败模式是桩拔出，其次是核折断；而纤维桩的主要失败模式是核脱粘，其次是核折断。
牙齿的抗折性随纤维桩长度的增加而成比例增加，随金属桩长度的增加而降低。当施加90°载荷时，不锈钢桩的抗折性比纤维桩更高。
