Ghasemi Negin, Torabi Zahra Sadat
Dept. of Endodontics, Dental and Periodontal Research Center, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
Dept. of Oral and Maxillofacial Surgery, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
J Dent (Shiraz). 2021 Sep;22(3):162-168. doi: 10.30476/DENTJODS.2020.85208.1118.
The efficacy of photodynamic therapy (PDT) in smear layer removal compared to the currently accepted protocol is not well established.
This study aims to evaluate the effect of PDT on smear layer removal from human root canal compared to combined use of irrigation solutions including sodium hypochlorite (NaOCl) and ethylene diamine tetra acetic acid (EDTA) by scanning electron microscopy (SEM).
In this study, straight roots from 48 extracted human maxillary incisors and canines were selected and decoronated. Instrumentation was completed with RaCe rotary system and normal saline irrigation between files. Then roots were randomly divided into 3 groups (n=16). Group 1 was the control group to confirm smear layer formation. In the group 2, the canals were irrigated with 2ml of 2.5% NaOCl solution for 10 minutes and 2ml of 17% EDTA solution for 1 minute. In the group 3, PDT with methylene blue and diode laser (625nm, 150mW, for 5minutes) was the final procedure for smear layer removal. All the specimens were sectioned into two halves, gold coated, and analyzed under SEM. The smear layer in the coronal, middle, and apical thirds, were evaluated and scored by two examiners independently. Statistical analysis was done using Chi-square test.
It was observed that the NaOCl+EDTA removed the smear layer significantly better than PDT in the coronal and apical thirds (< 0.05) whereas PDT was unable to remove the smear layer in none of the root areas. At the apical thirds, there was no significant difference between NaOCl+EDTA and PDT (< 0.05). Both procedures were unable to remove smear layer from radicular dentine of this area.
According to the results of this study, the use of PDT alone is not recommended to remove smear layer. The combined application of NaOCl and EDTA is ineffective in removing smear layer of apical third, despite its efficacy on the coronal and middle regions.
与目前公认的方案相比，光动力疗法（PDT）在去除玷污层方面的疗效尚未得到充分证实。
本研究旨在通过扫描电子显微镜（SEM）评估与联合使用包括次氯酸钠（NaOCl）和乙二胺四乙酸（EDTA）在内的冲洗液相比，PDT对去除人根管内玷污层的效果。
在本研究中，选取48颗拔除的人上颌切牙和尖牙的直根并去除冠部。使用RaCe旋转系统进行根管预备，每次换锉间用生理盐水冲洗。然后将根随机分为3组（n = 16）。第1组为对照组，以确认玷污层的形成。第2组中，根管先用2ml 2.5%的NaOCl溶液冲洗10分钟，再用2ml 17%的EDTA溶液冲洗1分钟。第3组中，用亚甲蓝和二极管激光（625nm，150mW，照射5分钟）进行PDT作为去除玷污层的最终步骤。所有标本均切成两半，进行镀金处理，并在SEM下进行分析。由两名检查者独立评估和评分冠部、中部和根尖三分之一处的玷污层。采用卡方检验进行统计分析。
观察到在冠部和根尖三分之一处，NaOCl + EDTA去除玷污层的效果明显优于PDT（<0.05），而PDT在任何根区均无法去除玷污层。在根尖三分之一处，NaOCl + EDTA与PDT之间无显著差异（<0.05）。两种方法均无法从该区域的根管牙本质上去除玷污层。
根据本研究结果，不建议单独使用PDT去除玷污层。尽管NaOCl和EDTA联合应用在冠部和中部区域有效，但在去除根尖三分之一处的玷污层方面无效。
