The microflora around the restorative material plays a crucial role in its survival. The study was performed to assess the antimicrobial property of the composites in the presence of Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Agar disc diffusion and Broth macro dilution methods were used on silorane and methacrylate based composite to study the microbes along with adhesion and penetration ability. Student’s t-test was performed to analyze antimicrobial activity and chi-square test (Fishers exact) to analyze adhesion and penetration assay, at a 5% level of significance. The materials tested were effective against S. mutans and C. albicans, with resistance to L. acidophilus. The silorane group presented better antimicrobial property in comparison to the methacrylate composite. Surface adhesion and penetration were reported to be higher in the methacrylate group than the silorane composite, however without a statistical significance. The antimicrobial effect and low adhesion capacity of the silorane based composite can be attributed to yttrium fluoride in the composition, which provides hydrophobicity to the surface. The antimicrobial property and hydrophobicity of the surface may enhance the durability of the esthetic restoratives clinically by an effective reduction in secondary caries. Keywords: adhesion capacity, antimicrobial activity, methacrylate based composite, penetration potential, silorane based composite https://doi.org/10.33887/rjpbcs/2020.11.1.21 *Corresponding
