Er:YAG激光和超声荡洗对根管内壁形态及微渗漏的比较研究

Comparison of root canal morphology and microleakage after cleaning with Er:YAG laser and ultrasonic irrigation

目的:观察不同参数Er:YAG激光和超声荡洗后对根管内壁形态及微渗漏产生的影响。方法:将81个离体下颌单根前磨牙随机分为阴性对照组(A组,生理盐水)、阳性对照组(B组,NaClO)、超声组(C组)、不同能量(0.3、0.6、0.9W)激光组(D、E、F组)、超声与不同能量(0.3、0.6、0.9W)激光联合组(G、H、I组)(n=9),根管预备后分别用各组对应的方法进行根管荡洗;然后从每组中各随机抽取6个牙根完成根管充填,经染料渗透实验后分别观察其染料渗透长度、面积;最后再取各组所余的3个牙根,分别沿其长轴劈开后用扫描电镜观察根管内壁形貌,计算牙本质小管的暴露率。结果:D组染料渗透长度最小,且各能量激光组(D^F组)的渗透长度均明显小于超声激光联合组(G^I组)(P<0.05);各组均以根尖部的染料渗透面积比率大于根上、根中部(P<0.05),各组内根上、中、尖3个部位的牙本质小管暴露率相比,均以根上部最大(P<0.05);组间相比,D、E组牙本质小管暴露率高于其他各组(P<0.05),但D、E两组间比较,P>0.05。结论:0.3W铒激光进行根管荡洗可最大化清除玷污层,效果优于超声荡洗。超声与激光联合并未减少微渗漏的发生,可造成根管内壁牙本质不同程度微裂。

AIM： To compare the root canal morphology and microleakage after cleaning with Er： YAG laser and ultrasonic irrigation. METHORDS： 81 extracted mandibular first premolars were divided into 9 groups（n = 9）,negitave control group（A,normal saline）,positive control group（B,Na Cl O）,ultrasonic group（C）,Er：YAG laser groups（0. 3 W,0. 6 W,0. 9 W）（D,E,F）,and combined groups（Er： YAG laser ＋ ultrasonic irrigation,0. 3 W,0. 6 W,0. 9 W）（G,H,I）. The teeth were instrumented and irrigated with PIPS technique and Er：YAG laser with different parameters and ultrasonic. Then 54 roots were tested with infiltration test for the measurements of the length and proportion of dye infitration,and 27 roots were observed with SEM for the analysis of inner morphology of root canals. RESURTS： The dye infiltration was shorter in Er： YAG laser group（D,E,F） than that in the combination groups（G,H,I）,and in group D was the shortest（P 〈 0. 05）. The proportion of dye infiltration was widest at apical root canals（P 〈 0. 05） than that at the coronal and middle part of root canals. SEM observation showed dentinal tubule exposure rate was the highest at coronal area in each group（P 〈 0. 05） and the exposure rate was higher in group D and E than that in other groups（P 〈 0. 05）. CONCLUSION： Er： YAG laser with 0. 3 W is more effective in clean up the smear layer than ultrasonic and the combination technique. Laser combined with ultrasonic irrigation may produce microleakage of root cannal dentine.