Evaluation of the Antibacterial Efficacy of Probiotics Lactobacillus Rhamnosus, Bifidobacterium Longum Over Calcium Hydroxide as Intracanal Medicament against Enterococcus Faecalis: An In Vitro study

INTRODUCTION: The long-term success of the endodontic treatment is the ultimate goal of every endodontist. In endodontics, even after the introduction of various new materials, traditional materials and methods is being used in routine endodontic treatment. The concept of the human microbiome is known to have better results in endodontic therapy after a few preliminary studies. The new concept of intentional introduction of microorganisms into the root canal and establishment of microbial equilibrium will decrease the number of pathogenic microorganisms thereby increasing the overall success rate of endodontic therapy. This study was performed to evaluate the use of probiotics concept in endodontic therapy. MATERIALS AND METHODS: Two groups of commercial available probiotics were selected and evaluated based upon numbers and concentration of organisms. Pathogenic test organism was E. faecalis (WVU Isolate Ef01). Phase 1 of the study was conducted by a disc diffusion assay test to evaluate zones of inhibition (ZOI) in millimeters (mm) of the selected probiotics against the Enterococcus faecalis. Microorganisms from probiotic samples were extracted via manufacturer’s recommendations and mixed by weight. Thirty (30) microliters were then placed on sterile discs. Pathogenic organisms were set to a 1 McFarland standard challenge. A two probiotic disc template on blood agar plates were inoculated with Enterococcus faecalis and incubated at 37° C for 48 hours and 1 week. Phase 2 was conducted by mixing 9 ml of 30% poloxamer 407 and MRS broth in a test tube, together with two probiotic mixtures and Enterococcus faecalis , set at a 2 McFarland standard. Serial dilutions upto 10 8 was done and the mixture was placed inside root canals and incubated at 37 degree Celsius for 36 hours and evaluated for CFU/ml counts. RESULTS: The results of phase one showed that probiotics Lactobacillus rhamnosus and Bifidobacterium longum are effective in fighting against Enterococcus faecalis with the acceptable zone of inhibition. The results of phase 2 where the probiotics were mixed with novel delivery vehicle poloxamer 407 to find the cumulative effect of the mixture against Enterococcus faecalis by determining the colony-forming unit, before and after administration of probiotics. The results showed that probiotics Lactobacillus rhamnosus and Bifidobacterium longum are effective against Enterococcus faecalis with a reduction in the number of colony-forming units after probiotic usage. CONCLUSION: Recognizing that probiotics may act differently based on their composition and concentration, this study suggests that organisms such as L. acidophillus, L. rhamnosus, L.casei and B. Longum are effective for preventing the growth of E. faecalis and C. albicans in vitro against both their planktonic and biofilm morphological stages. Further evaluations for possible use in treating endodontic infection is suggested and warranted. Additionally, Phase 2 results of the study suggest that poloxamer 407 could be utilized as an ideal probiotic delivery vehicle when mixed with appropriate probiotics and utilized as an endodontic intra-canal medicament for treating teeth that have presented with nonvital pulps