Bergmans L, Moisiadis P, Huybrechts B, Van Meerbeek B, Quirynen M, Lambrechts P
BIOMAT Research Cluster, Catholic University of Leuven, Leuven, Belgium.
Int Endod J. 2008 Mar;41(3):227-39. doi: 10.1111/j.1365-2591.2007.01344.x. Epub 2007 Dec 10.
To test the hypothesis that photo-activated disinfection (PAD) has a bactericidal effect on pathogens inoculated in root canals, with emphasis on biofilm formation/destruction.
Root canals of extracted teeth (n = 38) were prepared (size 30, 0.10 taper), autoclaved, divided into three groups and two negative controls inoculated (Streptococcus anginosus, Enterococcus faecalis or Fusobacterium nucleatum) and treated (PAD, laser, dye or positive control) according to a cross-sectional design. Resultant colony-forming unit counts were associated with observations of cell structural changes using environmental scanning electron microscopy (ESEM) on inoculated dentinal surfaces (n = 22, two controls) before (1, 2 and 6 days of incubation) and after treatment with PAD.
Treatment of root canals with PAD (15 J) caused a significant reduction of the bacterial load, resulting in a 93.8% kill of S. anginosus (P < 0.0001), a 88.4% kill of E. faecalis (P < 0.05) and a 98.5% kill of F. nucleatum (P < 0.0001), but no sterilization. Laser alone had no significant effect on the load nor did the dye without laser. The ESEM experiment showed that individual cells or monolayers were easily eliminated with PAD. But when biofilms were present (2 and 6 days for E. faecalis, 6 days for S. anginosus), bacterial eradication was substantially reduced in deep layers.
Photo-activated disinfection is not an alternative but a possible supplement to the existing protocols for root canal disinfection as the interaction between light (diode laser) and associated dye (TBO) provides a broad-spectrum effect. Some endodontic pathogens that grow as single-species biofilms, however, are difficult to eradicate.
验证光活化消毒（PAD）对接种于根管内病原体具有杀菌作用这一假说，重点研究生物膜的形成/破坏情况。
选取38颗拔除牙齿的根管，预备至30号、0.10锥度，高压灭菌后，根据横断面设计分为三组及两个阴性对照组，分别接种牙龈卟啉单胞菌、粪肠球菌或具核梭杆菌，并进行处理（PAD、激光、染料或阳性对照）。对接种牙本质表面（n = 22，两个对照组）在接种前（培养1、2和6天）及PAD处理后，使用环境扫描电子显微镜（ESEM）观察细胞结构变化，并对所得菌落形成单位计数。
用15 J的PAD处理根管可显著降低细菌载量，牙龈卟啉单胞菌杀灭率达93.8%（P < 0.0001），粪肠球菌杀灭率达88.4%（P < 0.05），具核梭杆菌杀灭率达98.5%（P < 0.0001），但未实现灭菌。单独使用激光对细菌载量无显著影响，未使用激光的染料也无影响。ESEM实验表明，PAD可轻易消除单个细胞或单层生物膜。但当存在生物膜时（粪肠球菌培养2和6天，牙龈卟啉单胞菌培养6天），深层细菌根除率大幅降低。
光活化消毒并非现有根管消毒方案的替代方法，而是一种可能的补充手段，因为光（二极管激光）与相关染料（甲苯胺蓝O）之间的相互作用具有广谱效应。然而，一些以单菌种生物膜形式生长的牙髓病原体难以根除。
