Influence of fluoride-doped calcium phosphates on the mineralisation, physicochemical properties and microbiological activity of glass ionomer cements

OBJECTIVES: This study evaluated the effects of incorporating fluoride-doped calcium phosphate (FDCP) into a glass ionomer cement (GIC) and a resin-modified glass ionomer cement (RMGIC) on their physicochemical properties, mineralisation potential, and antibacterial behaviour. METHODS: A conventional GIC (Riva SC, SDI Ltd., Australia) and RMGIC (Riva LC, SDI Ltd, Australia) were used to prepare experimental formulations containing different FDCP concentrations (SC 6%, SC 11 %, LC 13 %, and LC 18 %) and were compared with unmodified controls (SC-CTR, LC-CTR). Water sorption, solubility, uptake, pH, calcium and fluoride release, compressive strength and modulus, setting time, and microhardness were assessed. Mineral deposition on material surfaces and demineralised dentine was analysed using FTIR-ATR, SEM-EDX, and XRD after storage in artificial saliva (30 days). Antibacterial activity against Streptococcus gordonii was evaluated by metabolic activity, colony-forming units, and SEM. Cytotoxicity was assessed using human gingival fibroblasts. RESULTS: FDCP incorporation stabilised pH and influenced ion release behaviour in both materials. Increased mineral deposition was observed in FDCP-modified groups, with evidence of apatite-like precipitation, particularly in SC 11 %, LC 13 %, and LC 18 %. Improvements in long-term compressive strength and microhardness were mainly observed in the RMGIC formulations (LC 13 % and LC 18 %), as well as reduced bacterial metabolic activity and surface colonisation. However, reduced fibroblasts viability was also observed in all the tested groups under the test conditions. CONCLUSIONS: The incorporation of FDCP enhanced several functional properties of RGICs, particularly mineralisation and antibacterial behaviour, although some cytotoxic effects were also observed in all tested materials. CLINICAL SIGNIFICANCE: FDCP-modified GICs may improve the overal performance of GI-based restorative materials in clinical situations, as well as remineralisation and antibacterial activity.