Liu Jiayi, Watanabe Satoshi, Mochizuki Sota, Kouno Akira, Okiji Takashi
Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
J Dent Sci. 2023 Jul;18(3):1141-1147. doi: 10.1016/j.jds.2022.10.032. Epub 2022 Nov 9.
BACKGROUND/PURPOSE: Intracanal fractured instruments hamper adequate root canal disinfection. The aim of this study was to evaluate vapor bubble kinetics and cleaning efficacy of different irrigation techniques in the apical area beyond the fractured instrument.
Sixty curved root canal models, in which a 3-mm fragment of a #20 K-file or a WaveOne Gold Primary (WOG) instrument was intentionally separated at 3 mm from the apical foramen, were irrigated with laser-activated irrigation with photon-induced photoacoustic streaming (LAI-PIPS; 20 mJ/15 Hz), laser-activated irrigation using an Er:YAG laser unit (LAI; 30 mJ/20 Hz), or ultrasonic-activated irrigation (UAI) for 5 s. Vapor bubble velocity and counts were analyzed using high-speed video imaging. To evaluate canal wall cleanliness, 40 canals of extracted human teeth with an intentionally separated 3-mm WOG fragment in the canal at 3 mm from the apical foramen were irrigated with LAI-PIPS, LAI, UAI or conventional syringe irrigation, using 17% EDTA (30 s, two cycles), saline (30 s), and 3% NaOCl (30 s, three cycles) as irrigants. Debris and smear layer on the apical canal wall beyond the fractured instrument were scored using scanning electron microscopy.
LAI-PIPS and LAI demonstrated higher vapor bubble counts than UAI. The WOG fragment permitted higher bubble velocity and count than the K-file fragment. LAI-PIPS and LAI showed better debris and smear removal than the other techniques.
LAI and LAI-PIPS demonstrated higher vaporized bubble kinetics and better cleaning efficacy in the apical area, even in the presence of a fractured instrument.
背景/目的：根管内折断器械妨碍根管充分消毒。本研究的目的是评估不同冲洗技术在折断器械根尖区的气泡动力学和清洁效果。
制作60个弯曲根管模型，将#20 K锉或WaveOne Gold Primary（WOG）器械的3mm片段在距根尖孔3mm处故意折断，分别采用光子诱导光声流激光激活冲洗（LAI-PIPS；20 mJ/15 Hz）、使用铒激光装置的激光激活冲洗（LAI；30 mJ/20 Hz）或超声激活冲洗（UAI）冲洗5秒。使用高速视频成像分析气泡速度和数量。为评估根管壁清洁度，选取40颗拔除的人牙，根管内距根尖孔3mm处故意折断一个3mm的WOG片段，分别用LAI-PIPS、LAI、UAI或传统注射器冲洗，冲洗液分别为17%乙二胺四乙酸（EDTA，30秒，两个循环）、生理盐水（30秒）和3%次氯酸钠（30秒，三个循环）。使用扫描电子显微镜对折断器械根尖区根管壁上的碎屑和玷污层进行评分。
LAI-PIPS和LAI产生的气泡数量高于UAI。WOG片段比K锉片段产生的气泡速度更高、数量更多。LAI-PIPS和LAI在清除碎屑和玷污层方面比其他技术效果更好。
即使存在折断器械，LAI和LAI-PIPS在根尖区也表现出更高的汽化气泡动力学和更好的清洁效果。
