Seal G J, Ng Y-L, Spratt D, Bhatti M, Gulabivala K
Department of Conservative Dentistry, Eastman Dental Institute for Oral Health Care Sciences, University College London, UK.
Int Endod J. 2002 Mar;35(3):268-74. doi: 10.1046/j.1365-2591.2002.00477.x.
To compare the bacterial killing of Streptococcus intermedius biofilms in root canals using lethal photosensitization with various combinations of photosensitizer concentration and laser light dose or 3% sodium hypochlorite (NaOCl) irrigation.
Extracted teeth (n = 35) with single canals were selected and the canals prepared to apical size 25 with a 10% taper. The teeth were autoclaved and the canals inoculated with Streptococcus intermedius in brain heart infusion broth and were incubated for 48 h to allow a biofilm to form. The teeth were then subjected to 3% NaOCl irrigation (n = 4) or lethal photosensitization using combinations of a range of toluidine blue O (TBO) photosensitizer concentrations (12.5, 25, 50, 100 microgram/mL-1) and light doses (60, 90, 120, 300, 600 s equivalent to energy doses of 2.1-21 J) using a 35-mW helium-neon low power laser targeted at the access cavity (n = 4 for each combination). Controls consisted of laser light only (TBO = 0 microgram/mL-1) (n = 4), TBO only (light dose = 0 s) (n = 4), and no treatment (positive control n = 17). Following treatment the canal contents were sampled with sterile paper points, the sample was dispersed in transport medium, serially diluted and cultured on blood agar to determine the number of colony forming units (CFU).
The combination of 100 microgram/mL-1 TBO and 600 s (21 J) of laser energy achieved maximum reduction in recovered viable bacteria (5 log10 CFU). TBO at low concentrations (< or =50 microgram/mL-1) was not bactericidal but treatment with 100 microgram/mL-1 TBO alone reduced recovered viable bacteria by 3 log10 CFU. Laser light alone had limited bactericidal effect. No viable bacteria were recovered following treatment with 3% NaOCl.
The combined use of a photosensitizing agent and a low power laser directed at the access cavity was bactericidal to S. intermedius biofilms in root canals but was unable to achieve total kill, unlike 3% NaOCl.
比较使用不同浓度光敏剂与激光剂量组合的致死性光致敏作用以及3%次氯酸钠（NaOCl）冲洗对根管内中间链球菌生物膜的杀菌效果。
选取35颗单根管的离体牙，将根管预备至根尖尺寸25，锥度为10%。对牙齿进行高压灭菌，然后在脑心浸液肉汤中接种中间链球菌，孵育48小时以形成生物膜。之后，对牙齿进行3% NaOCl冲洗（n = 4），或使用一系列甲苯胺蓝O（TBO）光敏剂浓度（12.5、25、50、100微克/毫升-1）与光剂量（60、90、120、300、600秒，相当于能量剂量2.1 - 21焦耳）的组合进行致死性光致敏作用，使用35毫瓦氦氖低功率激光照射进入腔（每种组合n = 4）。对照组包括仅激光照射（TBO = 0微克/毫升-1）（n = 4）、仅TBO（光剂量 = 0秒）（n = 4）以及未处理（阳性对照n = 17）。处理后，用无菌纸尖采集根管内容物样本，将样本分散在运输培养基中，进行系列稀释并在血琼脂上培养，以确定菌落形成单位（CFU）的数量。
100微克/毫升-1 TBO与600秒（21焦耳）激光能量的组合使回收的活菌数量减少最多（5个对数10 CFU）。低浓度（≤50微克/毫升-1）的TBO无杀菌作用，但单独使用100微克/毫升-1 TBO可使回收的活菌数量减少3个对数10 CFU。仅激光照射的杀菌效果有限。用3% NaOCl处理后未回收活菌。
将光敏剂与低功率激光联合用于照射进入腔对根管内中间链球菌生物膜具有杀菌作用，但与3% NaOCl不同，无法实现完全杀灭。
