Depraet F J H W, De Bruyne M A A, De Moor R J G
Department of Operative Dentistry and Endodontology, Dental School, Ghent University, Ghent University Hospital, Gent, Belgium.
Int Endod J. 2005 May;38(5):302-9. doi: 10.1111/j.1365-2591.2005.00948.x.
To evaluate ex vivo the effect of Nd:YAG laser irradiation with and without black ink on instrumented root canal walls, and the degree of both coronal and apical microleakage of filled root canals.
Seventy-two single-rooted teeth were instrumented up to a size 40 K-file, and then divided into six groups of 10 teeth: groups 1 and 4 remained unlased and acted as control groups, groups 2 and 5 were treated with a Nd:YAG laser (Fidelis Plus, Herzele, Belgium), groups 3 and 6 were treated with a laser and black ink; the remaining 12 teeth served as positive and negative controls. The laser was operated at 1.5 W, 15 Hz, four times for 5 s with a 20-s interval. Groups 4-6 were filled using cold lateral condensation of gutta-percha and AH26. After storage in water for 48 h at 37 degrees C, through-and-through leakage (L in microL day-1) was measured for 48 h under a pressure of 1.2 atm using a fluid transport model and recorded as L=0 (L1), 0<L<or=10 (L2), L>10 (L3). After the assessment of leakage with the fluid transport model, the teeth were immersed in rhodamine B solution for 48 h at 37 degrees C. Apical and coronal dye leakage was scored after longitudinal splitting of these teeth. All teeth of groups 1-3 were split longitudinally and observed under SEM for evaluation of remaining smear layer.
Through-and-through leakage was only observed in the group lased with black ink (two samples-L2). Apical and coronal dye leakage was observed in all groups; there were no statistically significant differences amongst the three experimental groups. The through-and-through leakage, measured with the fluid transport model in two teeth of group 6, was confirmed in the dye leakage test (rhodamine B dye was observed along the total length of the root filling). There was evidence of melted and ablated root canal dentine in the laser-treated groups. These findings were more obvious in root canals lased in association with black ink. All apical foramina in the lased group remained patent.
Nd:YAG laser irradiation with black ink increased the amount of melted and ablated dentine areas compared with that without black ink. Nd:YAG lasing in association with black ink did not result in a reduction of either coronal or apical microleakage in root filled teeth.
体外评估钕钇铝石榴石（Nd:YAG）激光照射有无黑色墨水对预备后的根管壁的影响，以及根管充填后冠部和根尖微渗漏的程度。
将72颗单根牙预备至40号K锉，然后分为6组，每组10颗牙：第1组和第4组未接受激光照射，作为对照组；第2组和第5组用Nd:YAG激光（Fidelis Plus，比利时赫泽勒）治疗；第3组和第6组用激光和黑色墨水治疗；其余12颗牙作为阳性和阴性对照。激光以1.5W、15Hz运行，每次5秒，共4次，间隔20秒。第4 - 6组采用冷侧方加压法充填牙胶尖和AH26。在37℃水中储存48小时后，使用流体传输模型在1.2个大气压下测量48小时的贯通性渗漏（单位为微升/天，记为L），并记录为L = 0（L1）、0 < L ≤ 10（L2）、L > 10（L3）。在用流体传输模型评估渗漏后，将牙齿在37℃下浸入罗丹明B溶液中48小时。纵向劈开这些牙齿后对根尖和冠部染料渗漏进行评分。第1 - 3组的所有牙齿纵向劈开，在扫描电子显微镜下观察以评估残留的玷污层。
仅在使用黑色墨水激光照射的组中观察到贯通性渗漏（两个样本 - L2）。所有组均观察到根尖和冠部染料渗漏；三个实验组之间无统计学显著差异。在第6组的两颗牙齿中用流体传输模型测量的贯通性渗漏，在染料渗漏试验中得到证实（沿根管充填物全长观察到罗丹明B染料）。在激光治疗组中有根管牙本质熔化和消融的证据。这些发现在用黑色墨水激光照射的根管中更明显。激光照射组的所有根尖孔均保持开放。
与未使用黑色墨水相比，使用黑色墨水的Nd:YAG激光照射增加了牙本质熔化和消融的面积。使用黑色墨水的Nd:YAG激光照射并未导致根管充填牙的冠部或根尖微渗漏减少。
