机械预备与半导体激光对粪肠球菌杀菌作用的体外研究

Antibacterial efficacy of mechanical preparation and diode laser on enterococcus faecalis in vitro

目的:评价半导体激光对感染根管内粪肠球菌的杀菌效果。方法:成功建立粪肠球菌感染人单根管恒牙模型50个,用Pro Taper F3锉预备根管后随机分为5组(n=10),A组:空白对照,不照射激光;另4组分别用不同功率、时间半导体激光照射根管内壁,B组:1.0 W,10 s;C组:1.0 W,20 s;D组:2.0 W,10 s;E组:2.0 W,20 s。各组标本均于处理前、后在根管内壁表面取样并进行细菌培养计数;然后再分别用F4、F5锉依次预备并收集两种深度的牙本质碎屑,经厌氧培养后采用麦氏比浊法进行菌落计数。结果:1各组处理后的根管内壁细菌量均较处理前下降(P<0.05),各激光组细菌清除率均高于对照组(P<0.05),而各激光组之间两两相比差异无统计学意义(P>0.05);2各激光组均能使两种深度牙本质中的细菌量明显减少(P<0.05);其中照射10 s时,2.0 W比1.0 W的杀菌效果好(P<0.05),而照射20 s时,不同功率的杀菌效果无显著差异(P>0.05);用1.0 W时,照射20 s比10 s的杀菌效果好(P<0.05),而用2.0 W时,照射10、20 s的杀菌效果无差异(P>0.05)。结论:半导体激光对根管内壁及深层牙本质的粪肠球菌均有杀菌作用,其对牙本质深层的杀菌效果随着照射时间延长、功率增大而增强。

AIM： To evaluate the antibacterial efficacy of mechanical preparation and diode laser on enterococcus faecalis in infected root canals in vitro. METHODS： 50 single- rooted teeth of in vitro root canal enterococcus faecalis infection model were randomly divided into 5 groups（ n = 10）. The root canals of the teeth in the control group were prepared by Protaper F3. After F3 preparation,the tooth canals in the other 4 groups were treated with diode laser for 10 s and 20 s with 1. 0 W or 2. 0 W,respectively. Microbiological samples were collected from the root canals before and after irrigation. The dentin debris from two depths of the root canals were collected and cultured for turbidimetric count. A one-way ANOVA with the Tukey Test was conducted for the comparisons among the groups. RESULTS：The numbers of E. faecalis in all the groups decreased after treatment（ P〈0. 05）. The bacterieidal ration（ BR） of the treatment groups was higher than that of the control（ P〈0. 05）. Between each 2 laser groups,P〉0. 05. The number of E. faecalis from two different depths of dentin reduced in all the laser groups（ P〈0. 05）. Under the condition of10 s jrradiation,the disinfection was more effective with 2. 0 W than that with 1. 0 W,and there was no significant difference between 10 s irradiation and 20 s irradiation under the conditions of 2. 0 W irradiation. With 1. 0 W the disinfection was more effective by 20 s irradiation than by 10 s,and with 2. 0 W there was no significant difference between 10 s and 20 s irradiation. CONCLUSION： Diode laser is effective on root canal disinfection due to its effective penetration in dentins. The bactericidal effect enhances with increase of irradiation time and energy.