Chitosan-reinforced restorative materials: A systematic review protocol of in vitro studies on mechanical and biological properties

This systematic review aims to evaluate the effects of chitosan incorporation into dental restorative materials on mechanical properties, biocompatibility, and physical characteristics compared to non-reinforced formulations. BACKGROUND: Dental restorative materials are essential for managing dental caries and restoring tooth structure. However, conventional materials face limitations in mechanical strength, antimicrobial activity, and biocompatibility. Chitosan— a natural biopolymer derived from chitin deacetylation—possesses unique properties including biocompatibility, antibacterial activity, and biodegradability. Recent evidence suggests that chitosan incorporation can enhance mechanical properties and biological performance across various restorative material types. RESEARCH QUESTION: What are the effects of chitosan incorporation (any form, concentration, or molecular weight) into dental restorative materials (composite resin, glass ionomer cement, RMGIC, giomer, bonding agent, or luting cement) on mechanical properties, biocompatibility, and physical characteristics compared to conventional non-reinforced formulations? METHODS: We will systematically search PubMed, Scopus, and Embase for in vitro studies comparing chitosan-reinforced restorative materials with control/conventional materials. Study quality will be assessed using the OHAT tool. Data will be synthesized narratively with quantitative meta-analysis conducted if data homogeneity permits. EXPECTED OUTCOMES: Identify and quantify evidence on the efficacy of chitosan reinforcement across different restorative material types, establish optimal concentration and application strategies, and provide recommendations for clinical translation.