A Study on the Formation of Microbial Biofilms in the Infected Root Canals with refractory apical periodontitis, and on the Effect of Medicine against Biofilms

从40例难治性根尖牙周炎感染的根管中分离出173种微生物。其中铜绿假单胞菌（p.s.）、金黄色葡萄球菌（s.a.）、枯草芽孢杆菌（b.s.）、粪肠球菌（e.t.）和白色念珠菌（c.a.）。将其贴附于每个细胞盘上，用两种方法进行培养。一组用TS Broth（方法1）置于多板中，另一组悬挂在每个小瓶中（方法2）。方法二采用TS肉汤、TS肉汤加血浆和生理盐水加血浆作为培养基。37℃培养时间分别为3、7、14 d。然后用扫描电镜对每个细胞盘进行观察。除E.f.和c.a外，其余微生物均含有糖萼等物质。（方法1），除C.a（方法2）外，随培养时间延长而增加。此外，这些物质在介质中增加了等离子体。生物膜抗微生物药物采用FC（100%、10%、1%）、J（100%、10%、1%）、NaClO（10%、5%、1%）和氧化电位水。每种微生物在含血浆的TS肉汤中培养7天后，分别在每种药物中浸泡15分钟，再培养24小时和48小时。NaClO和氧化电位水仅用于S.a。未稀释的FC和J溶液对每种微生物都有效，但稀释后的溶液会降低效果。低浓度时，NaClO的作用也减弱。氧化电位水是低效的。难治性根尖牙周炎时，微生物可在根管根尖部形成生物膜。因此，似乎很难提供足够的药品。今后有必要对生物膜的破坏或融化方法进行研究。

173 microorganisms were isolated from 40 infected root canals with refractory apical periodontitis. Among them, Pseudomonas aeruginosa (P.s.), Staphylococcus aureus(S.a.), Bacillus subtilis(B.s.), Enterococcus faecalis(E.t.) and Candida albicans(C.a.) were used. They were adhered to each cell disk and cultured with two kinds of method. One was set in multiplate with TS Broth (method 1), and another was hanged in each small bottle (method 2). As the culture medium of method 2, TS Broth, TS Broth with plasma and saline with plasma were used . Culture periods were 3,7 andl4 days in 37ﾟC.Then each cell disk was observed with SEM.The substances like glycocalyx were observed in each microorganism except E.f. andC.a. (method 1), and except C.a.(method 2), increasing with the extension of culture period. Besides those substances increased in the medium adding plasma.As the medicine against microorganism with biofllm, FC (100%, 10%, 1%), J(100%, 10%, 1%), NaClO(l0%, 5%, 1%) and oxidative potential water were used. After cultivation in TS Broth with plasma for 7 days, each microorganism was immersed in each medicine for 15 minutes and cultured again for 24 and 48 hours. NaClO and oxidative potential water were only used for S.a..Undiluted solutions of FC and J were effective in each microorganism, but diluted solutions reduced the effect. The effect of NaClO also reduced in low concentration. Oxidative potential water was inefficient. Microorganisms can form bioflims in the apical portion of root canal with refractory apical periodontitis. So it seems to be difficult to supply sufficient medicine. In future it will be necessary to study about the method for destruction or melting of bioflims.