Correlation between DMFT index andoccurrence of Lactobacillus spp. in the oral cavity

The human oral cavity includes different bacterial community. Advantage and disadvantage of these bacteria depend on their ability to adhere to the tooth surfaces. Some microbiota could cause oral disease، however، some of them inhibit formation of biofilm on teeth and therefore prevent dental caries. The present study was undertaken to investigate on the DMFT index (D: decay، M: missing، F: filling، T: teeth) and the occurrence of different species of Lactobacillus، as the most important oral microbiota. Ninety swab samples were collected from saliva and teeth of the patients and subjected to microbiological analysis. Along with phenotypic and genotypic identifications of the isolates، the DMFT index of each patient was measured to determine the oral conditions. To continue the study the antibacterial effect of five commercial toothpastes was evaluated on the isolates. The results obtained indicated that the frequency of occurrence of L. plantarum، L. rhamnosus and L. mali was high in the patients with a low DMFT score and L. otakiensis، L. diolivorans and L. kefiri was high in the patients with a high DMFT score. Althoughall isolates were susceptible to the commercial tooth pastes، L. plantarum and L. rhamnosus were relatively more sensitive. Based on the results، human oral health might be affected by the population of Lactobacillusspp. Furthermore، use of toothpastes without adequate information concerning to their antimicrobial effects might eliminate the population of beneficial oral microbiotaand hence increase the risk of oral diseases.