Assessment of biological activity for thymol-doped methacrylate system as novel antibacterial dental restorative resin

Introduction Resin-based composites are currently utilized to overcome the short comings which esthetically associated with dental amalgam, although they suffer from some drawbacks such as shrinkage stress and shrinkage strain during their photochemical polymerization. Shrinkage stress and strain result in a failure and gap formation between the composite and tooth structure that would be the place for bacterial activity and secondary caries which result in composite failure. Objectives Over the past decades, the preparation of antibacterial restorative dental materials has obtained increasing attention in order to prevent secondary caries. Bactericidal agents should exhibit proper cytocompatibility as well as suitable bactericidal activity. In the present study a novel essential oil-based antibacterial resin matrix was prepared and evaluated for dental applications. In this regards, thymol, which is a major phenolic component of thyme essential oil, was incorporated in methacrylate resin matrix and samples were cured through photopolymerization reaction. Methods Quantitative assay of antibacterial activity of thymol-doped resins was evaluated through direct contact test against two common gram positive and gram negative bacterial strains i.e. S. aureus and E. coli, respectively. Direct contact cytotoxicity assay with fibroblast cell line L-929 was also performed to find more insight regarding cytotoxicity of the antibacterial matrixes. Results As it was expected the structural characteristic of thymol not only led to good miscibility with methacrylate resins but also gave rise to appropriate antibacterial activity as well as cytocompatibility. Conclusion The thymol-doped methacrylate system can be used as resin matrix of dental materials with acceptable biological activities.

Keywords:

Dental resins , Antibacterial activity , Thymol , Bioactive components