AIM To investigate the shaping and cleaning performance of the Clearsonic ultrasonic tip as a supplementary tool during the preparation of long oval-shaped root canals through micro-computed tomographic (micro-CT) imaging technology. The Reciproc M-Wire R40 instrument was used as a reference instrumentation technique for comparison. METHODOLOGY Twenty mandibular incisors with single, straight and long oval-shaped canals were selected and pair-matched by micro-CT scanning. The root canals were prepared with Reciproc R25 and R40 instruments, scanned again in a micro-CT device and randomly allocated into one of the two experimental groups (n = 10), according to the supplementary debridement protocol used: Clearsonic or Reciproc R40 used in a brushing motion against buccal and lingual walls. Noninstrumented canal areas, accumulation of hard-tissue debris (AHTD) and volume of removed dentine were assessed using micro-CT imaging following the supplementary debridement protocols. Data were analysed statistically in two phases using a t-test with a significance level of 5%. RESULTS In phase-1, there was a significant similarity between the samples regarding the evaluated micro-CT baseline parameters (P > 0.05), validating the anatomical similarity between the tooth pairs. In phase-2, there was a significant difference between the groups for canal volume, surface area, noninstrumented root canal walls and the amount of removed dentine for both absolute and percentage values (P < 0.05), but not for AHTD (P = 0.759). CONCLUSIONS The Clearsonic tip outperformed the Reciproc R40 instrument as a supplementary debridement protocol as it was associated with significantly greater reduction of noninstrumented root canals walls and consequently a larger amount of removed dentine. Both groups performed similarly regarding the AHTD.

中文翻译：

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箭头设计超声尖端作为根管清创的辅助工具。

目的通过微型计算机断层扫描（micro-CT）成像技术研究Clearsonic超声尖端作为辅助工具在长椭圆形根管预备过程中的整形和清洁性能。Reciproc M-Wire R40 仪器用作比较的参考仪器技术。方法 选择 20 颗单根直、长椭圆形根管的下颌切牙，通过显微 CT 扫描进行配对。根管用 Reciproc R25 和 R40 仪器准备，在 micro-CT 设备中再次扫描，并根据使用的补充清创方案随机分配到两个实验组之一 (n = 10)：Clearsonic 或 Reciproc R40 用于对颊和舌壁的刷牙动作。非仪器化运河区域，在补充清创方案之后，使用显微 CT 成像评估硬组织碎片 (AHTD) 的积累和去除的牙本质的体积。使用显着性水平为 5% 的 t 检验分两个阶段对数据进行统计分析。结果 在第 1 阶段，样本之间在评估的 micro-CT 基线参数方面存在显着相似性（P > 0.05），验证了牙齿对之间的解剖相似性。在第 2 阶段，绝对值和百分比值（P < 0.05），在根管容积、表面积、非器械根管壁和去除牙本质量方面存在显着差异（P < 0.05），但对于 AHTD 没有差异（P = 0.759 ）。结论 Clearsonic 尖端作为辅助清创方案优于 Reciproc R40 器械，因为它与非器械根管壁的显着减少有关，因此去除的牙本质量更大。两组在 AHTD 方面的表现相似。