Evaluation of the Role of Probiotics in Endodontic Treatment: A Preliminary Study

The principal goal of endodontics is the prevention of periapical infection. Acute and chronic apical periodontitis occur due to the persistence of pathogenic microorganisms such as Enterococcus faecalis and Candida albicans harboring the root canal systems of the teeth. The concept of the use of probiotics in addressing endodontic disease is new and has not been studied adequately. On the basis of the success of probiotics in periodontal treatment, this preliminary work was performed (a) to evaluate the antibacterial efficacy of probiotics against common endodontic pathogens, i.e. E. faecalis and C. albicans, and (b) to evaluate the potential use of probiotic therapy as an additive in endodontic treatment procedures.

Two commercial probiotics were selected and evaluated based upon the numbers and concentration of organisms. Pathogenic test organisms were C. albicans (ATCC 10231) and E. faecalis (ATCC 29212). Phase 1 of the study was conducted by agar cup method test to evaluate the antibacterial activity of the selected probiotics against E. faecalis and C. albicans by measuring zones of inhibition (ZOI) in mm. Microorganisms from probiotic samples were isolated following manufacturer's instructions. Pathogenic organisms were set to a 0.1 McFarland standard challenge. Circular wells of 8 mm diameter were punched in each of the poured plates. Appropriately diluted test samples were added to the above-punched wells. The volume of the solution added to each well was 100 μl. The plates were incubated in an upright position at 37°C for 24 hours under aerobic conditions. Post incubation, ZOI was measured (mm). Phase 2 was conducted by mixing 9 ml of 30% poloxamer 407 and de Man, Rogosa and Sharpe (MRS) broth in a test tube with 500 μl of either E. faecalis or C. albicans set at an optical density (OD) of 0.252, together with 500 μl of test probiotic strain, set at a respective OD. Samples were then incubated at 37°C for 48 hours, followed by serial dilutions by 1 ml till 10⁸. This was done to calculate colony forming units (CFU)/ml counts. Controls used were endodontic pathogens in 30% poloxamer with MRS broth without any probiotic group.

Probiotic groups showed inhibitory activity against E. faecalis by the agar cup method, whereas there was no effect on C. albicans. In the biofilm stage, both the test groups had an antibacterial effect on pathogenic organisms.

This study suggests that probiotic organisms of the species Lactobacillus and Bifidobacterium are effective for preventing the growth of E. faecalis and C. albicansin vitro. Because probiotics are available in varied compositions and concentrations, further evaluation for their role in treating endodontic infection is suggested and warranted. In addition, the study suggested that poloxamer 407 could be utilized as an ideal delivery vehicle for probiotics for use as a potential endodontic intracanal medicament.