Braun Andreas, Hagelauer Frederic Jean-Pierre, Wenzler Johannes, Heimer Matthias, Frankenberger Roland, Stein Steffen
1 Department of Operative Dentistry and Endodontology, University of Marburg , Marburg, Germany .
2 Department of Orthodontics, University of Marburg , Marburg, Germany .
Photomed Laser Surg. 2018 Nov;36(11):621-628. doi: 10.1089/pho.2018.4470. Epub 2018 Sep 27.
The aim of the present study was to investigate differences in the amount of dentin microcracking caused by the use of a 970-nm diode laser with different parameters for endodontic disinfection procedures.
Forty dental roots underwent mechanical endodontic preparation in a standardized manner. Each sample was randomly allocated to 4 groups receiving constant or interval laser irradiation time, calcium hydroxide disinfection, or a control group, with 10 samples per group. Transmission microscopy of all samples was performed at T0, before preparation; T1, immediately after endodontic preparation; and T2, after laser application in the laser groups and after 1 week of storage in the control and calcium hydroxide groups. The microcracks at each measurement point were color labeled, layered, and compared.
No significant differences were noted at T0 and T1 (p > 0.05). Statistically significant differences in the overall amount of microcracking were observed between the constant laser group and all other groups at T2 (p < 0.05). There were no statistically significant differences between the interval laser group, the calcium hydroxide group, and the control group at T2 in relation to the overall amount of microcracking (p > 0.05). When the root sections were analyzed separately, the coronal section did not show any statistically significant differences between the constant laser and interval laser groups (p > 0.05). The middle and apical root sections in the constant laser group showed the significantly largest amount of crack formation in comparison with the other groups (p < 0.05). The statistically significantly smallest amount of crack formation was observed in the apical third for all groups (p < 0.05).
Clinically proposed laser protocol seems to be able to prevent side effects to the tissue, such as microcracks of the root canal dentine.
本研究旨在调查使用970纳米二极管激光并采用不同参数进行根管消毒程序时，牙本质微裂纹数量的差异。
40颗牙根以标准化方式进行机械根管预备。每个样本随机分为4组，分别接受持续或间歇激光照射时间、氢氧化钙消毒，或作为对照组，每组10个样本。所有样本在制备前（T0）、根管预备后立即（T1）以及激光组激光照射后和对照组与氢氧化钙组储存1周后（T2）进行透射显微镜检查。对每个测量点的微裂纹进行颜色标记、分层并比较。
在T0和T1时未观察到显著差异（p > 0.05）。在T2时，持续激光组与所有其他组之间在微裂纹总量上观察到统计学显著差异（p < 0.05）。在T2时，间歇激光组、氢氧化钙组和对照组在微裂纹总量方面无统计学显著差异（p > 0.05）。当分别分析牙根切片时，冠部切片在持续激光组和间歇激光组之间未显示任何统计学显著差异（p > 0.05）。与其他组相比，持续激光组的牙根中部和根尖部切片显示出显著最多的裂纹形成（p < 0.05）。在所有组的根尖三分之一处观察到统计学上显著最少的裂纹形成（p < 0.05）。
临床建议的激光方案似乎能够预防对组织的副作用，如根管牙本质的微裂纹。
