Antibacterial Activity of the Combination of Calcium Hydroxide and Ellagic Acid towards Enterococcus faecalis and Lactobacillus acidophilus

Calcium hydroxide is a material commonly used in pulp capping because of its substantial antibacterial property. However, this antibacterial property of calcium hydroxide is less effective on Enterococcus faecalis and Lactobacillus acidophilus due to their resistance factors. Ellagic acid is a natural phenolic acid with extraordinary antibacterial properties. Combining calcium hydroxide with ellagic acid is expected to enhance its antibacterial properties towards Enterococcus faecalis and Lactobacillus acidophilus. This study aimed to determine the antibacterial activity of the combination of ellagic acid and calcium hydroxide on Enterococcus faecalis and Lactobacillus acidophilus. A suspension of Enterococcus faecalis and Lactobacillus acidophilus bacteria comparable to a McFarland standard 0.5 of 1.5 x 108CFU/ml was made. Three different calcium hydroxide and ellagic acid ratios were made by mixing 0.099g, 0.097g, and 0.095g calcium hydroxide powder with 0.001g, 0.003g, and 0.005g ellagic acid powder, respectively. These powder mixtures were then added with 0.1 mL of sterile distilled water. Four Mueller Hinton Petri dishes were divided into four sections each. The mixtures of these powders were applied to the petri dish with the diffusion method. There are significant differences (p<0.05) between every group for Lactobacillus acidophilus. Similar results are also observed between all groups of Enterococcus faecalis except for group 5 (ratio 97:3) and group 6 (ratio 95:5). The combination of ellagic acid and calcium hydroxide decreases the zone of inhibition of Enterococcus faecalis and Lactobacillus acidophilus.