Characterisation of experimental flowable composites containing fluoride-doped calcium phosphates as promising remineralising materials

Remineralising composites with antibacterial properties may seal the cavity and prevent secondary caries. This study aimed at developing experimental flowable composites containing different concentrations of fluoride-doped calcium phosphate fillers and evaluating their remineralising and antibacterial properties. Experimental resin-based composites containing different concentrations (0-20%) of fluoride-doped calcium phosphate fillers (VS10/VS20) were formulated. The release of calcium (Ca), phosphate (PO) and fluoride (F) ions was assessed for 30 days. Remineralisation properties were evaluated through ATR-FTIR and SEM/EDX after storage in simulated body fluid (SBF). The metabolic activity and viability of Streptococcus gordonii was also evaluated through ATP, CFU and live/dead confocal microscopy. The evaluation of specific monomer elution from the experimental composites was conducted using high-performance liquid chromatography (HPLC). The composites containing VS10 showed the highest release of Ca, those containing VS20 released more F over time (p0.05). A quick 7-day mineral precipitation was observed in the tested composites containing VS10 or VS20 at 10%; these materials also showed the greatest antibacterial activity (p<0.05). Moreover, the tested composites containing VS10 presented the lowest elution of monomers (p<0.05). Innovative composites were developed with low monomers elution, evident antibacterial activity against S. gordonii and important remineralisation properties due to specific ions release. Novel composites containing fluoride-doped calcium phosphates may be promising to modulate bacteria growth, promote remineralisation and reduce the risk of cytotoxicity related to monomers' elution.