ObjectivesThis study aimed to identify oral Lactobacillus species and characterize their adhesion properties and antibacterial activity in patients with periodontitis compared with periodontally healthy individuals.Materials and MethodsThree hundred and fifty‐four isolates from the saliva, subgingival, and tongue plaque of 59 periodontitis patients and 59 healthy individuals were analyzed. Oral Lactobacillus species were identified through the culture method in the modified MRS medium and confirmed by molecular testing. Moreover, the radial diffusion assay and cell culture methods were used to determine the antibacterial activities of oral strains against oral pathogens and their adhesion activity in vitro.Results67.7% of the cases and 75.7% of the control samples were positive for the Lactobacillus species. Lacticaseibacillus paracasei and Limosilactobacillus fermentum were the dominant species in the case group, whereas Lacticaseibacillus casei and Lactiplantibacillus plantarum were dominant in the control group. Lactobacillus crispatus and Lactobacillus gasseri had higher antibacterial effects against oral pathogens. Moreover, Ligilactobacillus salivarius and L. fermentum demonstrated the highest ability to adhere to oral mucosal cells and salivary‐coated hydroxyapatite.ConclusionL. crispatus, L. gasseri, L. fermentum, and L. salivarius can be introduced as probiotic candidates since they demonstrated appropriate adherence to oral mucosal cells and salivary‐coated hydroxyapatite and also antibacterial activities. However, further studies should be conducted to assess the safety of probiotic interventions using these strains in patients with periodontal disease.

Background and aim: Chronic periodontitis has been defined as an infectious disease resulting in inflammation within the dental supporting tissue, progressive attachment loss and bone resorption. Nowadays, with increasing microbial resistance, bacterial therapy is an alternative to prevent inflammatory diseases of the oral cavity, which regulates oral microbiota and eliminating pathogenic bacteria. The aim of this study was to identify oral Lactobacillus species and in patients with periodontitis and healthy individuals. Materials & Methods: Use of specific culture medium and restriction fragment-length polymorphism (RFLP) analysis was applied to characterize oral lactobacillus in oral cavity samples (saliva, tongue, gingival plaque) from 59 healthy subjects and 59 patients with chronic periodontitis. The 16srDNA genes of lactobacillus .spp in samples were amplified by PCR with universal primers. Sequencing performed to confirm the species. Results: Out Of 354 examined isolates, 254 isolates were positive for Lactobacillus based on culture and PCR results. From obtained strain cutting patterns analysis of the oral lactobacillus community, were aggregated into ten different species. L.paracasei, L.fermentumin patient and L.casei, L.plantarum were the most predominant species in control groups. Conclusion: The frequency of Lactobacillus in patients with periodontitis was significantly reduced comparing to the control group, especially in gingival plaque samples. The difference in the frequency of isolated lactobacillus in the total sample of patients was 8% less than control subjects. There is increasing evidence that the use of existing lactobacillus strains can prevent chronic periodontitis. These probiotic candidates can be selected for the purpose of bacteriotherapy, dairy manufacture and pharmaceutical use.