Antimicrobial and physicochemical properties of experimental light curing composites with alkali-substituted calcium phosphate fillers

ObjectiveThe antimicrobial and physicochemical properties of experimental light curing composites prepared with fillers made of mechanically activated alkali-substituted calcium phosphates like CaKPO4, CaNaPO4 or Ca2KNa(PO4)2 were compared with a commercial silane-modified cristobalite filler.MethodsThe antimicrobial properties were tested using Streptococcus mutans, Staphylococcus aureus and a clinically isolated plaque mixture. The potential for reducing bacteria growth on modified composites was determined using the proliferation reagent WST-1, which enables the measurement of metabolic activity and therefore the colonization with living bacteria. Investigated material properties included the degree of conversion and a test of flexural strength.ResultsAll alkali-substituted composites provide a changed, mainly basic micro-milieu leading to a reduction of bacteria population with respect to the non-modified composite of about 25–70% with a flexural strength of cured composites in the range of 55–77 MPa complying with the clinical standard and a degree of conversion of 44–66%.SignificanceThis study suggests that the modified composites increase antimicrobial properties while basic composite characteristics are not influenced by the filler.