Correlation between Bond Strength to Dentin and Sealers Penetration by Push-Out Test and CLSM Analysis

Abstract This study correlated the bond strength (BS) and dentin penetration of different sealers by push-out test and Confocal Laser Scanning Microscopy (CLSM) analysis. Forty-five root canals were prepared according to the crown-down technique and filled with gutta-percha associated to the following sealers (n=15): Endofill, AH Plus and MTA Fillapex. Five canals of each group were filled with the sealers added with 0.1% Rhodamine B dye. Next, the specimens were transversely sectioned and submitted to the push-out test (n=10) and CLSM analysis (n=5). The BS data showed the following means (MPa) and standard deviation: AH Plus (4.17±1.86); MTA Fillapex (3.13±1.96) and Endofill (2.10±1.03). Statistical analysis (two-way ANOVA, α=0.05) showed significant difference among sealers (p<0.001) and root canal thirds (p<0.001). The BS results of Endofill and MTA Fillapex were statistically similar (p>0.05), however, they were statistically different from AH Plus (p<0.001). The regional analysis of BS showed similarity between middle and apical thirds (p>0.05), and both were different from coronal portion (p<0.001). CLSM analysis verified tags formation in all groups and higher penetration of the specimens filled with AH Plus (p<0.05). The Kendall test (correlation between BS to dentin and sealer penetration into dentinal tubules) and the Pearson test (between failures pattern and sealer penetration into dentinal tubules) did not show correlation between the variables evaluated for all the tested sealers (p>0.05). AH Plus group had higher BS to dentin, and deeper tags formation than the other sealers. There was no significant correlation between BS and intratubular penetration of the tested sealers.

摘要 本研究通过推出试验与激光扫描共聚焦显微镜（Confocal Laser Scanning Microscopy, CLSM）分析，探究不同根管封闭剂的牙本质粘结强度（bond strength, BS）与牙本质渗透能力之间的相关性。本研究共制备45个根管样本，采用冠向下预备技术进行根管预备，随后使用牙胶尖联合3种封闭剂进行根管充填（每组n=15）：Endofill、AH Plus及MTA Fillapex。其中每组各5个根管采用添加了0.1%罗丹明B染料的封闭剂进行充填。随后将所有标本横向切片，每组分别选取10个样本开展推出试验，5个样本进行激光扫描共聚焦显微镜分析。
粘结强度检测数据的均值（单位：MPa）与标准差如下：AH Plus组为4.17±1.86，MTA Fillapex组为3.13±1.96，Endofill组为2.10±1.03。双因素方差分析（检验水准α=0.05）结果显示，不同封闭剂组间以及根管三分区的粘结强度均存在显著统计学差异（p<0.001）。Endofill组与MTA Fillapex组的粘结强度无统计学差异（p>0.05），但二者均与AH Plus组存在显著差异（p<0.001）。粘结强度的区域分析显示，根管中1/3与根尖1/3的粘结强度无统计学差异（p>0.05），且二者均与冠部1/3存在显著差异（p<0.001）。
激光扫描共聚焦显微镜分析证实，所有组别均形成了牙本质粘结突，且AH Plus组充填标本的封闭剂渗透深度更高（p<0.05）。Kendall相关分析（用于评估牙本质粘结强度与封闭剂牙本质小管渗透能力的相关性）与Pearson相关分析（用于评估破坏模式与封闭剂牙本质小管渗透能力的相关性）结果显示，所有受试封闭剂的各观测变量间均无显著相关性（p>0.05）。AH Plus组的牙本质粘结强度更高，且牙本质粘结突形成深度优于其余两组；受试封闭剂的牙本质粘结强度与小管内渗透能力之间未发现显著相关性。