Investigation of Microorganisms in Infected Dental Root Canals

Objective: The purpose of this study is to investigate the type of microorganisms isolated from necrotic pulp tissues and from failed endodontic treatments in infected root canals. Methods: This study is based on an experiment conducted on 90 patients between November, 2002 and November, 2003 using a sampling. One hundred single root canals were microbiologically sampled from these patients by using sterile paper points. Among 100 canals sampled, 61 had primary infection and 39 had a history of secondary infection. Microorganisms were isolated and identified by using established advanced microbiologic techniques for anaerobic species. Results: A total of 197 cultivable isolates were recovered, the microbial findings in both types of canals, such as the number of species isolated, the 68.0% of Gram-positives and 27.9% gram-negatives, the 52.8% of facultative and 43.1 % strict anaerobic microorganisms 4.1% fungi and so on. Ten canals presented no microbial growth. Conclusions: The prevalence of bacteria and fungi found in 100 root canals is the prevalence of the microbial genera in primary and secondary endodontic infection. Peptostreptococcus spp was the most predominantly isolated microbial genera, followed by Streptococcus spp (14.2%), Porphyromonas spp (12.2%), E. faecalis (9.6%), Staphylococcus salivarius (8.6%), Prevotella spp (8.1%), Lactobacillus spp (7.1%), Actinomyces spp (7.1%), Candida albicans (4.1%), Fusobacterium spp (3.6%) Veillonella spp (2.5%), Eubacterium spp (2.5%), Bacillus spp (2.0%), and Escherichial coli (1.6%) were other types of bacteria recovered.