Plotino Gianluca, Buono Laura, Grande Nicola M, Lamorgese Vincenzo, Somma Francesco
Department of Endodontics, Catholic University of Sacred Heart, Rome, Italy.
J Prosthet Dent. 2008 Mar;99(3):225-32. doi: 10.1016/S0022-3913(08)60047-5.
When cuspal coverage is required, there is no evidence that indirect composite resin restorations are superior to direct restorations in terms of biomechanical behavior.
The purpose of this in vitro study was to compare the fracture resistance of cusp-replacing direct and indirect composite resin restorations in endodontically treated molars.
Forty-five human mandibular molars were selected and divided into 3 groups (n=15): DIR specimens, restored with direct composite resin (Estelite Sigma) restorations; IND specimens, restored with indirect composite resin (Estelite Sigma) restorations, and control specimens, which remained intact. Endodontic treatment was performed using NiTi ProTaper rotary instruments, and teeth were filled using lateral condensation of gutta-percha and sealer. Extensive Class II MO cavities were prepared, and the 2 mesial cusps were reduced, allowing a 2-mm layer of composite resin. All teeth were prepared to the same dimensions, considering reasonable human variation. Specimens were loaded to failure and the fracture loads were recorded (N). The mode of fracture was determined using a stereomicroscope and classified as favorable or unfavorable failure. The data were subjected to a Kruskal-Wallis test, multiple-comparison Mann-Whitney test, and a chi-square test (alpha=.05).
Significant differences (P<.001) were observed between the control group and both DIR and IND groups. However, no significant difference was found between the DIR and IND groups. The chi-square test did not show a significant difference in the frequencies of favorable/unfavorable failure modes among the 3 groups (P=.981).
No significant difference was observed in the fracture resistance of endodontically treated molars restored to original contours with an extensive cusp-replacing direct or indirect composite resin restoration.
当需要覆盖牙尖时，尚无证据表明间接复合树脂修复体在生物力学行为方面优于直接修复体。
本体外研究的目的是比较根管治疗后磨牙中直接和间接复合树脂牙尖替代修复体的抗折性。
选取45颗人下颌磨牙，分为3组（n = 15）：直接修复组（DIR），用直接复合树脂（Estelite Sigma）修复；间接修复组（IND），用间接复合树脂（Estelite Sigma）修复；以及完整未修复的对照组。使用镍钛ProTaper旋转器械进行根管治疗，并用牙胶尖侧方加压充填和封闭剂充填牙齿。制备广泛的II类近中-牙合面洞型，磨除两个近中牙尖，预留2mm的复合树脂层。考虑到合理的个体差异，将所有牙齿制备成相同尺寸。对标本加载直至破坏，并记录破坏载荷（N）。使用体视显微镜确定破坏模式，并分为有利或不利破坏。数据进行Kruskal-Wallis检验、多重比较Mann-Whitney检验和卡方检验（α = 0.05）。
对照组与DIR组和IND组之间均观察到显著差异（P < 0.001）。然而，DIR组和IND组之间未发现显著差异。卡方检验显示3组中有利/不利破坏模式的频率无显著差异（P = 0.981）。
对于根管治疗后的磨牙，用广泛的牙尖替代直接或间接复合树脂修复体恢复至原始外形时，其抗折性无显著差异。
