VARIATIONS IN THE SUSCEPTIBILITIES OF COMPONENTS OF THE ENDODONTIC MICROFLORA TO BIOMECHANICAL PROCEDURES

The role of the endodontic micoflora in pulpal disease and in endodont ic treatment failures is well established, Thus the need for effective microbial control is one of the important justifications for biomecha nical procedures, However the efficacy of this stage of treatment is d ependent upon the vulnerability of the involved species, which may not be uniform. The aim of this study was to investigate variations in th e susceptibilities of members of the root canal microflora to routine biomechanical procedures, Forty-two root canals were investigated micr obiologically. Samples were collected before and after instrumentation and the bacterial findings were compared, In 15 cases of 'primary' ro ot canal therapy, despite changes in the population size, no significa nt change in the species composition of the microflora was observed, H owever in 27 cases 'secondary' treatment, a decrease in the number of isolations of Peptostreptococcus spp, was found (P = 0.008). When all 42 cases were considered together, significant decreases were found be tween first and second samples for anaerobes (P = 0.0117) and for Gram positive species (P = 0.008), especially Peptostreptococcus spp, (P = 0.02). It was therefore concluded that certain species are more resist ant to the biomechanical procedures than others.