AIM To evaluate the influence of various endodontic access cavity designs and the use of an operating microscope (OM) with or without ultrasonic troughing to detect middle mesial canals (MMCs) in extracted mandibular first molars. METHODOLOGY Sixty extracted mandibular first molars were evaluated by cone beam computed tomography (CBCT) in order to detect the presence of MMCs and then divided into two groups (n = 30) with an equal proportion of 1 molar with MMC for each 3 molars. A specific access cavity design was performed for each group, either a conservative access cavity (CAC) or a traditional access cavity (TAC). Root canals were detected in three assessment stages: (i) no magnification, (ii) using an OM and (iii) using an OM together with ultrasonic troughing. Evaluations were performed on a mannequin head in an ergonomic working position. The confidence obtained in the assessment stages was portrayed by sensitivity, specificity and accuracy, calculated by the area under the ROC curve. The difference in the proportion of correct diagnoses in identifying the MMC using either CAC or TAC preparation, at each of the three stages, was checked using Cochran's Q tests. Binomial tests were performed at each stage to investigate whether there was a difference between the types of endodontic access designs to detect MMCs. Significance was set at P < 0.05. RESULTS Accuracy increased at each assessment stage. At the third stage, both groups provided perfect accuracy (1.00). Cochran's Q tests indicated that the confidence of MMC detection for both TAC and CAC groups (P < 0.05) increased significantly at each stage. Binomial tests demonstrated that there was no significant difference between the TAC and CAC groups, when evaluation was performed without magnification (P > 0.05), with OM (P > 0.05), or with OM associated with ultrasonic troughing (P > 0.05). CONCLUSION The access cavity design did not significantly affect detection of middle mesial canals in extracted mandibular first molars placed in a mannequin. However, the use of OM increased the accuracy of the MMC identification, especially when associated with ultrasonic troughing.

中文翻译：

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出入腔设计的影响以及手术显微镜和超声槽的使用对检测下颌第一磨牙中中膜的影响。

目的评估各种牙髓进入腔设计的影响，以及在有无超声槽的情况下使用手术显微镜（OM）来检测下颌第一磨牙中的中间系膜管（MMC）的使用。方法学通过锥束计算机断层扫描（CBCT）评估了60个提取的下颌第一磨牙，以检测MMC的存在，然后分为两组（n = 30），每3磨牙与MMC的比例相等，为1磨牙。为每个组执行了特定的进入腔设计，无论是保守进入腔（CAC）还是传统进入腔（TAC）。在三个评估阶段中检测出根管：（i）无放大倍数，（ii）使用OM，以及（iii）使用OM和超声槽。在人体工学工作位置上对人体模型头部进行评估。通过ROC曲线下的面积计算出的敏感性，特异性和准确性描述了评估阶段获得的置信度。在三个阶段中的每个阶段，使用Cochran's Q检验检查使用CAC或TAC制剂识别MMC时正确诊断比例的差异。在每个阶段都进行了二项式检验，以调查用于检测MMC的牙髓入路设计类型之间是否存在差异。显着性设定为P <0.05。结果在每个评估阶段，准确性均得到提高。在第三阶段，两组都提供了完美的准确性（1.00）。Cochran的Q检验表明，在每个阶段，TAC和CAC组的MMC检测置信度均显着提高（P <0.05）。二项式检验表明，在不进行放大（P> 0.05），OM（P> 0.05）或与超声波谷相关的OM（P> 0.05）的情况下进行评估时，TAC组和CAC组之间没有显着差异。结论出入腔的设计并没有显着影响放置在人体模型中的下颌第一磨牙中中肠管的检测。但是，OM的使用提高了MMC识别的准确性，尤其是在与超声波槽相关联时。结论出入腔的设计并没有显着影响放置在人体模型中的下颌第一磨牙中中肠管的检测。但是，使用OM可以提高MMC识别的准确性，尤其是在与超声波谷相关的情况下。结论出入腔的设计并没有显着影响放置在人体模型中的下颌第一磨牙中中肠管的检测。但是，使用OM可以提高MMC识别的准确性，尤其是在与超声波谷相关的情况下。