Trends in pH-Triggered Strategies for Dental Resins Aiming to Assist in Preventing demineralization: a scoping review

Objectives: To identify and map the literature on the current state of pH-triggered strategies for resin-based materials used in direct restorative dentistry, focusing on innovative compounds, their incorporation and evaluation methods, and the main outcomes.

Data and sources: Through a search across PubMed, Scopus, Embase, Web of Science, LILACS, Cochrane Library databases, and Google Scholar, this review identified studies pertinent to pH-responsive dental materials, excluding resin-modified glass ionomer cements.

Study selection: From the 981 records identified, 19 in vitro studies were included, concentrating on resin-based composite resins (50%), dentin adhesives (25%), and sealants (25%). The review identified diverse pH-triggered strategies based on ion release, antibacterial release, antibacterial no release, association of contact-antibacterial compounds with acid neutralizer, and combined ion and antibacterial releasing systems for the development of pH-responsive dental materials. Despite the incorporation of innovative compounds such as nanoparticulated amorphous calcium phosphate (20%), tetracalcium phosphate (40%), chlorhexidine-loaded mesoporous silica nanoparticles (10%), tertiary amine dodecylmethylaminoethyl methacrylate (5%), and bioactive glass with 4% nano-POSS (20%), the mechanical integrity of the materials remained satisfatory, displaying flexural strength and elastic modulus that were similar to or better than control. Materials showcased pH-dependent release of calcium and phosphate ions, especially in acidic conditions, and potential for prevention of tooth demineralization, indicating decreased mineral loss and lesion depth.

Conclusions: In general, ion releasing and antibacterial-based strategies alone or associated, comprising the incorporation of amorphous calcium phosphate, tetracalcium phosphate, chlorhexidine-loaded mesoporous silica nanoparticles, tertiary amine dodecylmethylaminoethyl methacrylate, and bioactive glass with 4% nano-POSS were used to provide pH-responsiveness for composite resins, adhesive systems, or sealants, without compromise of the mechanical properties, and with promising potential for enhancing caries prevention.

Clinical relevance: Advancements on smart pH-responsive dental resins based on ion-releasing and antibacterial associated strategies may contribute to prevent or reduce bacterial acid formation and demineralization of tooth structure at the interface between tooth tissues and restoration, possibly favoring the success of restorative treatment in the future.