Antimicrobial effect of different intracanal medications on various microorganisms

To compare the antimicrobial effect of Calcium hydroxide paste (CaOH), Chlorhexidine gluconate (CHX) gel and Antibiotic- Corticosteroid paste against Streptococcus mutans, Enterococcus faecalis and Candida albicans in root canal lumen and radicular dentin. Materials and methods: Eighty four single rooted extracted human teeth with straight root canals were selected, decronated leaving root segments of 15 mm length. All canals were prepared up to size 40 master apical file under irrigation with sodium hypochlorite solution. Roots were sterilized, infected by mixed suspension of the three types isolated microorganisms and incubated at 37 ℃ for 14 days. The roots were divided into 4 equal groups according to the intracanal medications used. Group I: CaOH, Group II: CHX, Group III: Antibiotic-Corticosteroid paste and Group IV: saline. Each main group was further equally subdivided into 3 subgroups according to the isolated organism. Subgroup (A): S. mutans, Subgroup (B): E. faecalis and Subgroup(C): C. albicans. The medicated roots were incubated for 7 days at 37 ℃ then irrigated to remove the medications. Two samples were taken from each canal, one from root canal lumen and the other from radicular dentin and cultured on three media selective for each tested microorganisms. The growing colonies were counted and recorded as colony forming units CFU. Results: Chlorhixidine gel showed the best effect against all tested microorganisms at both experimental sites, while Antibiotic- Corticosteroid paste was the worest one. Conclusion: CHX was the best medication used to eliminate the different tested organisms at the two experimental sites. S. mutans was the most sensitive microorganism to the whole tested medications, while C. albicans was the most resistant one.