Er∶YAG激光光子增强的光声流效应技术清理根管玷污层效果的体外研究

Irrigation effectiveness of removing smear layers with Er∶YAG shock wave enhanced emission photoacoustic streaming:an in vitro study

目的观察不同Er∶YAG激光技术对根管内壁玷污层的清理能力,探究光子增强的光声流效应(shock wave enhanced emission photoacoustic streaming,SWEEPS)技术对根管内壁玷污层的清理效果。方法示波器精确测定Er∶YAG激光不同工作模式的脉冲波形。收集人离体第三磨牙(85颗),使用机用ProTaper Universal镍钛锉进行根管预备至30号(锥度0.09),建立玷污层模型,并使用5.25%次氯酸钠在预备过程中进行冲洗。分别应用Er∶YAG激光SWEEPS技术与光子诱导的光声流效应(photon-induced photoacoustic streaming,PIPS)技术激活17%EDTA,清理离体牙根管内壁玷污层30 s和60 s。将激光激活荡洗后的样本沿牙体组织长轴纵向劈开,扫描电镜分别观察距离根尖孔1、4及8 mm的根管内表面并进行评分。红外热像仪记录两种不同Er∶YAG激光技术激活荡洗时离体牙外表面的温度变化。结果 SWEEPS技术是一种双脉冲Er∶YAG激光工作模式,该技术对距离根尖孔4 mm及1 mm的玷污层清理效果优于PIPS技术(P <0.05)。红外热像仪检测发现两种Er∶YAG激光技术在激活荡洗过程中对牙周膜的热负效应差异无统计学意义(P> 0.05)。结论与PIPS技术相比,应用Er∶YAG激光SWEEPS技术可对根中段及根尖段玷污层有更好的清理效果,同时不增加对牙周膜的热负效应。

Objective To analyze the characteristics and smear layer removing efficiency of shock wave enhanced emission photoacoustic streaming(SWEEPS),a new Er:YAG laser agitation technique.Methods The waveform characteristics were detected by an oscilloscope.Totally 85 third molars in vitro were prepared by ProTaper Universal Nickel titanium mechanical instrument and irrigated with standardized 5.25% sodium hypochlorite.Final irrigation was performed under photon-induced photoacoustic streaming(PIPS)technique and SWEEPS technique for 30 s and 60 s,respectively,using conical tip and 17% EDTA.The specimens were split longitudinally.The residual smear layer within the root canal was evaluated under scanning electron microscopy at 8,4 and 1 mm from the apex.Thermal infrared imager was used to measure the temperature changes on the outer surface of the roots.Results The SWEEPS technique is a dual pulse modality.The smear layer removal efficiency of the SWEEPS technique was significantly higher,compared to PIPS technique,at 4 mm and 1 mm from the apex(P <0.05).During the entire irrigation process,no statistical difference was found in average temperature increase between SWEEPS and PIPS technique(P> 0.05).Conclusion Compared with PIPS technique,SWEEPS technique has better effect in cleaning smear layer at middle root and apex,and does not increase the thermal side effect on periondontal membrane.