Department of Endodontics, School of Dentistry, Evangelical University of Goiás.
Department of Stomatology, School of Dentistry, Federal University of Goiás.
J Oral Sci. 2023;65(3):190-194. doi: 10.2334/josnusd.23-0048.
To investigate the effects of two ultrasonic vibration protocols for cast post removal (single or double ultrasound units) on the development of defects in root dentin.
Sixty bovine incisors were selected. Fifteen roots were left unprepared (control). Forty-five roots were instrumented and filled. A 10-mm post space was prepared using #1-4 Largo drills. Fifteen teeth were prepared for post space and received no further procedure. Thirty roots had cast posts cemented and were submitted to ultrasonic vibration protocols for removal. The time necessary to remove each post was recorded. Roots were sectioned 3, 6, 9, and 12 mm from the coronal portion and viewed through a 25× magnification in a stereomicroscope. The presence of root fractures, partial cracks, and craze lines was registered. Chi-square and Fisher's exact tests were performed to compare the incidence of dentin defects. The Kruskal-Wallis test was performed to explore the difference between the time needed for post removal. The significance level was set at P = 0.05.
Root defects were observed in all experimental groups. There were no statistical differences comparing previous root canal treatment and post removal steps, either with 1 or 2 ultrasonic units, in the formation of defects (P = 0.544) or fractures (P = 0.679).
Ultrasonic vibration protocols for removing cast posts did not increase the number of dentin defects compared to root canal preparation and obturation and post space preparation steps.
研究两种超声振动方案（单次或双超声单元）对铸造桩取出后牙本质缺陷发展的影响。
选择 60 颗牛切牙。15 根根未经预处理（对照）。45 根根被器械处理和填充。使用#1-4 Largo 钻头制备 10mm 的桩腔。15 颗牙被制备桩腔但未进行进一步处理。30 颗根牙粘固铸造桩，并进行超声振动方案取出。记录每个桩去除所需的时间。将根部分别从冠部切取 3、6、9 和 12mm 长，并在立体显微镜下以 25×放大倍数观察。记录根折、部分裂纹和微裂纹线的存在。采用卡方检验和 Fisher 确切概率法比较牙本质缺陷的发生率。采用 Kruskal-Wallis 检验探索去除桩所需时间的差异。显著性水平设定为 P = 0.05。
所有实验组均观察到根缺陷。与根管预备和充填以及桩腔预备步骤相比，无论使用 1 个还是 2 个超声单元，在形成缺陷（P = 0.544）或根折（P = 0.679）方面，前次根管治疗和去除桩步骤之间无统计学差异。
与根管预备和充填以及桩腔预备步骤相比，去除铸造桩的超声振动方案并未增加牙本质缺陷的数量。
