J Adhes Dent. 2018;20(6):519-526. doi: 10.3290/j.jad.a41635.
The aim of this ex-vivo study was to evaluate the load capacity of direct or indirect endodontically restored maxillary central incisors with Class III defects, with or without glass-fiber posts.
Seventy-two extracted human maxillary central incisors were endodontically treated and bi-proximal Class III cavities were prepared. Specimens were randomly allocated to six groups (n = 12): direct restoration with composite (C); direct restoration with composite and additional glass-fiber post (CP); ceramic veneer restoration (V), ceramic veneer restoration and additional glass-fiber post (VP), ceramic crown restoration (Cr), ceramic crown restoration and additional glass-fiber post (CrP). Specimens were exposed to thermomechanical loading (TML: 1.2 million cycles, 1 to 50 N; 6000 thermal cycles between 5°C and 55°C for 1 min each), and subsequently linearly loaded until failure (Fmax [N]) at an angle of 135 degrees 3 mm below the incisal edge on the palatal side. Statistical tests were performed using the Kruskall-Wallis and Mann-Whitney U-Test.
During dynamic loading by TML, one early failure occurred in group C, CP, and CrP. Subsequent linear loading resulted in mean fracture load values [N] of C = 483 ± 219, CP = 536 ± 281, V = 908 ± 293, VP = 775 ± 333, Cr = 549 ± 258, CrP = 593 ± 259. The Kruskal-Wallis test showed significant differences of load capacity between groups (p < 0.05). Mann-Whitney U-test revealed significantly lower maximum fracture load values of group C compared to group V (p = 0.014), after Bonferroni-Holm correction. Non-restorable root fracture was the most frequent type of failure.
Endodontically treated maxillary central incisors with Class III defects directly restored with composite are as loadable as indirect crown restorations. Compared to full-coverage restorations, less invasive veneers appear to be more beneficial. Additional placement of glass-fiber posts shows no positive effect.
本体外研究旨在评估直接或间接根管治疗后的上颌中切牙伴有 III 类缺损的牙体剩余结构的负载能力，以及是否使用玻璃纤维桩。
72 颗上颌中切牙经根管治疗后，制备双侧近中 III 类洞型。样本随机分为 6 组（n = 12）：复合树脂直接修复（C）；复合树脂直接修复，附加玻璃纤维桩（CP）；陶瓷贴面修复（V）；陶瓷贴面修复，附加玻璃纤维桩（VP）；全瓷冠修复（Cr）；全瓷冠修复，附加玻璃纤维桩（CrP）。样本接受热机械循环加载（TML：120 万次循环，1 至 50 N；6000 个热循环，每个循环 5°C 至 55°C 持续 1 分钟），然后在 135°、切缘下 3mm 处的腭侧以 3mm 为半径进行线性加载，直至破坏（Fmax[N]）。使用 Kruskal-Wallis 和 Mann-Whitney U 检验进行统计检验。
在 TML 动态加载过程中，C、CP 和 CrP 组各发生 1 次早期失效。随后进行线性加载，得出 C 组的平均断裂载荷值[N]为 483 ± 219，CP 组为 536 ± 281，V 组为 908 ± 293，VP 组为 775 ± 333，Cr 组为 549 ± 258，CrP 组为 593 ± 259。Kruskal-Wallis 检验显示组间负载能力存在显著差异（p < 0.05）。Mann-Whitney U 检验显示，经 Bonferroni-Holm 校正后，C 组的最大断裂载荷值明显低于 V 组（p = 0.014）。最常见的失效类型为不可修复的根折。
直接用复合树脂修复的伴有 III 类缺损的上颌中切牙与间接冠修复体具有相同的可负载能力。与全冠修复相比，微创贴面修复更具优势。附加玻璃纤维桩的使用没有显示出积极的效果。
