Mixing ratio of nano hydroxyapatite and Epigallocatechin-3-gallate (EGCG) towards viscosity and antibacterial effect as a potential pulp capping Material: An experimental study

Background: Finding a new natural scaffold is challenging due to crucial impact on long-term treatment outcomes in pulp capping. In this context, nano hydroxyapatite (nano-HA) is a potential candidate having similar properties to bone tissue in the body. The compound is often synthesized with Epigallocatechin-3-gallate (EGCG) which offers anti-inflammatory and antibacterial properties. Therefore, this study aims to contribute novel insights into the development of effective pulp capping materials by determining the viscosity ratio of the combination of nano-HA and EGCG applied to the cavity according to standard pulp capping material, as well as proving the antibacterial effect against Lactobacillus acidophilus. Methods: The combination of nano-HA – EGCG is divided into three treatment groups, (G1) 1:1 ratio, (G2) 1:1.5 ratio, (G3) 1:2 ratio, as well as control group G4 (Ca(OH)₂ and aquadest) with a ratio of 1:1. Meanwhile, each group is tested for viscosity using a Brookfield viscometer. The well diffusion method is used to determine the antibacterial activity by measuring the diameter of the inhibition zone for each treatment, with C1 (Ca(OH)₂ and aquadest) as control group at a ratio of 1:1, and three treatment groups (nano-HA – EGCG), (C2) 0.5:1 ratio, (C3) 1:1 ratio, and (C4) 2:1 ratio. Results: The results show that there is a difference in the viscosity of each group with G3 having a viscosity of 12.0183 cP, which is closest to control. Furthermore, significant differences are also reported in antibacterial activity between control and treatment groups. Conclusion: The ratio of 1:2 (G3) has a viscosity that closely matches the standard of pulp capping materials. The combinations of nano-HA and EGCG are proven to have antibacterial power against Lactobacillus acidophilus.