AIM To evaluate the influence of ultraconservative endodontic access cavities (UEC) on gaps and void formation in resin composite restorations in extracted two-rooted maxillary premolars after root canal treatment. Traditional endodontic access cavities (TEC) were used as a reference for comparison. METHODOLOGY Two-rooted maxillary premolars were scanned in a micro-computed tomographic (micro-CT) device, matched based on similar anatomical features and allocated into two groups (n = 10) according to the design of the access cavity: TEC or UEC. Teeth were mounted on a mannequin head and a single operator performed the treatment, including endodontic access cavity preparation, root canal detection, preparation, filling and restoration procedures, under magnification. For restorative procedure, a bulk fill flowable layer was applied initially followed by an overlaying of regular composite. After restoration procedures, a new micro-CT scan was performed to check the quality of the coronal restoration by analysing the percentage volume of empty spaces present in the tooth-restoration interface (gaps) and inside the restoration (voids). Data were analysed statistically using Shapiro-Wilk and Student's t tests with a significance level of 5%. RESULTS All specimens had gaps and voids. There were significant differences between the access cavity designs regarding the formation of voids with significantly more voids associated with the UEC (P < 0.05). Gap formation did not differ between groups (P > 0.05). CONCLUSION The access cavity design used during root canal treatment interfered with the adaptation of the restorative material. The minimally invasive access cavity design was associated with a significantly greater number of voids within restorations.

中文翻译：

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拔牙后根管治疗后通道腔设计对树脂复合材料修复体中间隙和空隙形成的影响。

目的评估根管治疗后拔除的两根上颌前磨牙的超保守牙髓根管腔对UEC树脂修复体间隙和空隙形成的影响。传统的牙髓进入腔（TEC）被用作比较的参考。方法在微计算机断层扫描（micro-CT）装置中扫描两根上颌前磨牙，根据相似的解剖特征进行匹配，并根据进入腔的设计将其分为两组（n = 10）：TEC或UEC。将牙齿安装在人体模型的头部，由一名操作员在放大的情况下进行治疗，包括牙髓进入腔的准备，牙根管的检测，准备，填充和修复程序。对于恢复程序，最初应用大块填充的可流动层，然后覆盖常规复合材料。修复程序完成后，通过分析牙齿修复界面（间隙）和修复体内部（空隙）中存在的空白区域的百分比，进行了新的微型CT扫描以检查冠状修复体的质量。使用Shapiro-Wilk和Student's t检验对数据进行统计学分析，显着性水平为5％。结果所有标本都有空隙和空隙。在进入腔的设计之间存在明显的差异，即与UEC相关的空隙的形成明显更多（P <0.05）。各组之间的间隙形成没有差异（P> 0.05）。结论在根管治疗中使用的进入腔设计干扰了修复材料的适应性。