Progress in dental materials: application of natural ingredients

The existing additives for dental restorative materials used in therapeutic dentistry, dentures, orthodontic appliances and adhesives (for example, metal and metal oxide nanoparticles) and also additives to root canal irrigants used in endodontics and to mouthwashes can be toxic to humans, cause allergic reactions and accumulate in organs and tissues. Today, a relevant trend is development of dental materials that have an antimicrobial effect and are non-toxic to humans. A promising alternative to the above-mentioned additives are phyto-components, including plant and propolis extracts, since they are cheap and non-toxic. This review is devoted to natural antimicrobial additives to dental materials used in orthodontics, dentures, therapeutic dentistry and endodontics. The review makes recommendations regarding additional research required for practical implementation of the considered dental materials (filling materials, mouthwashes, orthodontic adhesives and orthopaedic dental products), examines the influence of antimicrobial additives on the physicochemical and physicomechanical properties of polymer dental materials, and outlines the advantages and disadvantages of natural additives compared to synthetic ones. The main challenges in this research area are the narrow range of microorganisms for which the antimicrobial effect was studied (which are mainly S. mutans, E. faecalis, C. albicans) and the predominance of in vitro studies over clinical studies. The review covers published data of the past five years. The bibliography includes 123 references.