Strontium-Containing Biomaterials in Dentistry: Mechanisms of Remineralisation and Clinical Translation - A Systematic Review

Strontium has emerged as a promising component in biomaterials, enhancing remineralisation of dental hard tissues through ionic substitution, bioactivity, and modulation of apatite formation. It has been integrated into strontium-doped nano-hydroxyapatite, bioactive glasses, and fluorophosphates, each exploiting distinct structure–function mechanisms. This systematic review evaluates the efficacy of strontium-containing biomaterials for enamel and dentin remineralisation, with focus on physicochemical properties, mechanisms of action, and translational potential. A systematic review of in vitro studies was conducted, including strontium-enriched formulations applied to enamel and/or dentin. Outcomes included changes in surface microhardness (ΔSMH) and lesion depth. Owing to heterogeneity in designs, formulations, and measures, findings were synthesised narratively using SWiM (Synthesis Without Meta-analysis) guidelines. Twenty-one in vitro studies were identified; only one used a bovine tooth model, and no human clinical trials were found. Twelve reported >30% enamel ΔSMH improvement, with Sr-doped nano-hydroxyapatite achieving gains up to 45%. Sr-bioactive glass and Sr–fluoride hybrids reduced lesion depth by 15–25%, with several studies showing synergistic effects with fluoride. To conclude, strontium-based biomaterials show promising potential for enhancing enamel remineralization and caries prevention; however, current evidence is derived exclusively from in vitro studies. Well-designed in vivo clinical trials are therefore essential before these findings can be reliably translated into clinical practice.