Detection of endodonticpathogens in root canalsof deciduous teeth bymolecular techniques

Aim: This study aimed to assess the efficacy of two molecular methods, namely PCR assay and checkerboard DNA-DNA hybridization, for the detection of specific endodontic pathogens in the root canals of deciduous teeth with primary endodontic infection. It also aimed to investigate the most prevalent species detected regardless of the method used. Methods: Samples were taken from 44 cases of deciduous teeth with primary endodontic infection. DNA was extracted and the presence of microorganisms was checked by using PCR assay and checkerboard DNA-DNA hybridization assay. Fisher´s exact test was used to observe the possible difference in the prevalence of each pathogen concerning the molecular methods. Sensitivity, specificity, and accuracy tests were performed between both methods. The statistical significance level was 5%. Results: In our study, PCR and checkerboard DNA-DNA hybridization had specificity higher than sensitivity, demonstrating that these assays can identify true-negative samples. Both methods showed a similar capacity to detect specific endodontic pathogens in root canals of deciduous teeth with primary endodontic infection. PCR and checkerboard showed no statistically significant differences for most species detected, except four species: P. micra and P. nigrescens, which were more prevalent by PCR, and F. alocis and P. intermedia, which were more prevalent by checkerboard DNA-DNA hybridization. Conclusions: In conclusion, both methods are efficient in detecting endodontic pathogens and one should complement the other. Taking together the results from both methods, A. naeslundii and F. nucleatum were the most prevalent species.