Division of Endodontics, Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
Eur Endod J. 2023 Jan;8(1):65-71. doi: 10.14744/eej.2022.96720.
To test the hypothesis that the (i) presence of non-carious cervical lesions (NCCLs) and (ii) type of post system have no effect on the fracture resistance and pattern in endodontically treated maxillary premolars.
Human maxillary first premolars (n=60) with two root canals were randomly allocated into four groups (n=15). Buccal wedge-shaped NCCLs were prepared in 45 teeth specimens. Following root canal treatment, the specimens were randomly divided into (i) composite resin core (CRC); (ii) NCCLs + composite resin core (NCCL+CRC); (iii) NCCLs+prefabricated fibre-reinforced composite post + composite resin core (NCCL+PFRC+CRC); (iv) NCCLs+custom fibre posts + composite resin core (NCCL+CFP+CRC). All specimens were subjected to thermocycling (5°C to 55°C/5000 cycles). The compressive load was applied non-axially to the palatal cusp with a universal testing machine at a crosshead speed of 0.5 mm/min at a 30° angle until fracture. Fracture patterns were examined using a loupe magnification (2.5×) under transillumination. Statistical analyses were performed using non-parametric tests and pairwise comparisons of the load-to-fracture among the groups. Chi-square test was used to analyse the fracture patterns (P=0.05).
Fracture resistance of NCCL+PFRC+CRC was significantly higher than NCCL+CRC (P=0.011), while NCCL+CFP+CRC did not show any significant difference when compared to NCCL+CRC (P=0.089). No statistical difference was found between CRC, NCCL+PFRC+CRC and NCCL+CFP+CRC (P=1.000). The frequencies of favourable fracture patterns in descending orders were as follows: CRC (80%), NCCL+CFP+CRC (73%), NCCL+PFRC+CRC (60%), and NCCL+CRC (40%). Chi-square test did not show significant differences in fracture patterns among all groups (P=0.110).
Restoration of the endodontically treated maxillary premolars with NCCLs, with or without post, resulted in similar fracture resistance as their counterparts without NCCLs. Placement of a prefabricated fibre-reinforced composite post exhibited greater fracture resistance to the maxillary premolars with restored NCCLs than those without a post. (EEJ-2022-06-077).
验证以下假设，即（i）非龋性颈领病变（NCCL）的存在和（ii）桩系统的类型对上颌前磨牙根管治疗后的抗折强度和模式没有影响。
本研究将 60 个人类上颌第一前磨牙随机分为 4 组（每组 15 个）。45 个牙体标本制备颊侧楔形 NCCL。根管治疗后，将标本随机分为（i）复合树脂核（CRC）；（ii）NCCL+复合树脂核（NCCL+CRC）；（iii）NCCL+预制纤维增强复合材料桩+复合树脂核（NCCL+PFRC+CRC）；（iv）NCCL+定制纤维桩+复合树脂核（NCCL+CFP+CRC）。所有标本均进行热循环（5°C 至 55°C/5000 次循环）。使用万能试验机以 0.5mm/min 的十字头速度在 30°角向腭尖施加非轴向压缩载荷，直至发生断裂。使用放大镜（2.5×）在透照下检查断裂模式。使用非参数检验和组间载荷-断裂的两两比较进行统计分析。卡方检验用于分析断裂模式（P=0.05）。
NCCL+PFRC+CRC 的抗折强度明显高于 NCCL+CRC（P=0.011），而 NCCL+CFP+CRC 与 NCCL+CRC 相比无显著差异（P=0.089）。CRC、NCCL+PFRC+CRC 和 NCCL+CFP+CRC 之间无统计学差异（P=1.000）。按降序排列，有利断裂模式的频率如下：CRC（80%）、NCCL+CFP+CRC（73%）、NCCL+PFRC+CRC（60%）和 NCCL+CRC（40%）。卡方检验显示各组间的断裂模式无显著差异（P=0.110）。
对于伴有或不伴有桩的根管治疗后的上颌前磨牙，修复 NCCL 后其抗折强度与无 NCCL 的前磨牙相似。预制纤维增强复合材料桩的放置使具有修复 NCCL 的上颌前磨牙的抗折强度大于无桩的前磨牙。
