Department of Endodontics, School of Dentistry, State University of Rio de Janeiro (UERJ), Rio de Janeiro, Brazil.
Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Rio de Janeiro, Brazil.
Int Endod J. 2020 Dec;53(12):1666-1679. doi: 10.1111/iej.13383. Epub 2020 Sep 15.
To assess the impact of conservative endodontic access cavities (CEC) and truss access cavities (TAC) during root canal treatment performed on mandibular molars in terms of: ability to shape and fill root canals, microbial reduction in canals, and cleaning of the pulp chamber. In addition, the fracture resistance of the teeth after coronal restoration was assessed. Traditional endodontic cavities (TEC) were used as a reference technique for comparison.
Thirty extracted intact mandibular molars were scanned in a microcomputed tomography device (micro-CT), matched based on similar anatomical features and assigned to TEC, CEC or TAC groups (n = 10). The specimens were accessed accordingly, and root canals were contaminated with bacterial suspensions of Enterococcus faecalis (21 days). Subsequently, the first microbial sample was collected from root canals (S1). The canals were initially prepared with Reciproc Blue R25 instrument followed by a second instrumentation using Reciproc Blue R40. Eight mL of 0.5% NaOCl were used as an irrigant for each instrument. A final irrigation protocol was performed with 2 mL of 0.5% NaOCl, 2 mL of 17% EDTA and another 2 mL of 0.5% NaOCl. Microbial samples were collected from root canals after R25 (S2), R40 (S3) and final irrigation (S4). The teeth were rescanned after S4. Then, root canals were filled, rescanned, restored and the teeth subjected to fracture resistance tests. The statistical analysis was performed with type I negative binomial and beta 0-1 inflation regression models for microbiological analysis. Instrumentation, filling and resistance to fracture results were subjected to anova and Tukey tests (P < 0.05).
S4 revealed no significant variations in microbial reduction amongst the groups (P > 0.05). TEC had a significantly lower percentage of unprepared surface area than CEC (P < 0.05). No differences were found regarding the percentage of dentine removed, transportation, centring ability and filling voids amongst the groups (P > 0.05). The TEC group had a significantly lower volume of remaining root filling material within the pulp chamber than CEC and TAC groups (P < 0.05). There was no difference regarding fracture resistance amongst the groups (P > 0.05).
Conservative access cavities did not offer any advantage in comparison with the traditional endodontic cavities in any of the parameters considered. Furthermore, conservative methods were associated with larger percentages of unprepared canal surface area and larger volumes of remaining root filling material within the pulp chamber.
评估在下颌磨牙根管治疗中使用保守性根管入口（CEC）和桁架式根管入口（TAC）对根管成形和填充、根管内微生物减少以及牙髓腔清洁的影响。此外，还评估了根管治疗后牙齿的抗折能力。传统的根管入口（TEC）被用作比较的参考技术。
将 30 颗完整的下颌磨牙在微计算机断层扫描设备（micro-CT）中进行扫描，根据相似的解剖特征进行匹配，并分为 TEC、CEC 或 TAC 组（n=10）。相应地进行标本访问，并将细菌悬液 Enterococcus faecalis 污染根管（21 天）。随后，从根管中收集第一个微生物样本（S1）。使用 Reciproc Blue R25 器械初步准备根管，然后用 Reciproc Blue R40 进行第二次器械准备。每次仪器使用 8mL 0.5% NaOCl 作为冲洗液。用 2mL 0.5% NaOCl、2mL 17% EDTA 和另外 2mL 0.5% NaOCl 进行最终冲洗方案。用 Reciproc Blue R25 （S2）、R40 （S3）和最终冲洗（S4）后从根管中收集微生物样本。S4 后对牙齿进行重新扫描。然后，根管填充、重新扫描、修复，对牙齿进行抗折试验。微生物分析采用 I 型负二项式和 beta 0-1 膨胀回归模型进行统计分析。仪器准备、填充和抗折试验结果采用方差分析和 Tukey 检验（P<0.05）。
S4 显示各组之间的微生物减少没有显著差异（P>0.05）。TEC 的未预备表面积百分比明显低于 CEC（P<0.05）。各组之间的牙本质去除百分比、运输、中心定位能力和填充空隙无差异（P>0.05）。TEC 组牙髓腔内剩余根管填充材料的体积明显小于 CEC 和 TAC 组（P<0.05）。各组之间的抗折强度无差异（P>0.05）。
与传统的根管入口相比，保守性根管入口在任何参数方面都没有优势。此外，保守方法与更大的未预备根管表面面积百分比和更大的牙髓腔内剩余根管填充材料体积相关。
