Department of Restorative Dentistry, Dental School of University of Passo Fundo, Passo Fundo, RS, Brazil.
Department of Restorative Dentistry, Dental School of University of Passo Fundo, Passo Fundo, RS, Brazil.
J Mech Behav Biomed Mater. 2020 Jun;106:103736. doi: 10.1016/j.jmbbm.2020.103736. Epub 2020 Mar 23.
To evaluate the effect of different endodontic irrigation protocols on dentin mechanical properties and fracture resistance of roots with 0.5 mm (weakened roots) and 1.5 mm of thickness.
Irrigation protocols were the following: Distilled water (DW) + Ethylenediamine tetraacetic acid (EDTA); grape seed extract (GSE) + EDTA; sodium hypochlorite (NaOCl) + EDTA; NaOCl + EDTA + GSE; calcium hypochlorite (Ca(ClO)) + EDTA; Ca(ClO) + EDTA + GSE; chlorhexidine (CHX) + EDTA; CHX + EDTA + GSE. The samples were prepared and the values of microhardness, ultimate tensile strength (UTS), and flexural strength were obtained. Further, fracture resistance of roots with dentin thickness of 0.5 mm and 1.5 mm, and restored with fiberglass post relined with composite resin and metal crowns, were evaluated with same irrigation protocols previously described; the failure mode was evaluated as well. All tests presented normality in data distribution (Kolmogorov-Smirnov), and Analysis of Variance and Bonferroni test (α = 0.05) were performed.
Higher reduction of dentin microhardness was observed in the NaOCl and NaOCl + EDTA + GSE groups (p < 0.0001). An increased in the UTS values was obtained in the CHX groups (p < 0.0001), while similar values were observed between the control and other groups (p > 0.05). The reduction of dentin flexural strength was observed in the NaOCl groups (p < 0.0001), while no significant changes were observed in the other groups (p > 0.05). With regard to fracture resistance, no statistical difference was obtained among the irrigation's protocols (p > 0.05), except for CHX (p = 0.0031) and CHX + GSE (p = 0.0001) that showed increased in fracture resistance values in roots with 1.5-mm thickness. An increased rate of irreparable failure was obtained in the NaOCl groups, whereas there was a predominance of repairable failure in the other groups.
The endodontic irrigation protocol has a significant impact on the dentin mechanical properties; on the other hand, do not reduce the fracture resistance of root with 0.5 mm and 1.5 mm of thickness.
评估不同根管冲洗方案对 0.5 毫米（薄弱根）和 1.5 毫米厚的牙根的牙本质力学性能和抗折性能的影响。
冲洗方案如下：蒸馏水（DW）+乙二胺四乙酸（EDTA）；葡萄籽提取物（GSE）+EDTA；次氯酸钠（NaOCl）+EDTA；NaOCl+EDTA+GSE；次氯酸钙（Ca（ClO））+EDTA；Ca（ClO）+EDTA+GSE；洗必泰（CHX）+EDTA；CHX+EDTA+GSE。制备样本并获得显微硬度、极限拉伸强度（UTS）和弯曲强度值。此外，还评估了用相同的冲洗方案处理牙本质厚度为 0.5 毫米和 1.5 毫米的牙根的抗折强度，并用玻璃纤维桩和复合树脂以及金属冠修复，还评估了相同的冲洗方案处理牙本质厚度为 0.5 毫米和 1.5 毫米的牙根的抗折强度，并评估了失效模式。所有测试的数据分布均呈正态分布（Kolmogorov-Smirnov），并进行方差分析和 Bonferroni 检验（α=0.05）。
NaOCl 和 NaOCl+EDTA+GSE 组牙本质显微硬度降低更明显（p<0.0001）。CHX 组 UTS 值增加（p<0.0001），而对照组和其他组之间的 UTS 值无显著差异（p>0.05）。NaOCl 组牙本质弯曲强度降低（p<0.0001），而其他组无明显变化（p>0.05）。关于抗折强度，除 CHX（p=0.0031）和 CHX+GSE（p=0.0001）外，各组冲洗方案之间无统计学差异（p>0.05），这两组的抗折强度值在 1.5 毫米厚的牙根中增加。NaOCl 组不可修复性失败的发生率增加，而其他组以可修复性失败为主。
根管冲洗方案对牙本质力学性能有显著影响，但不会降低 0.5 毫米和 1.5 毫米厚的牙根的抗折强度。
