Antibacterial Property Expressed by a Novel Calcium Phosphate Glass

Objective: Bone regenerative materials have been successful in the treatment of osseous defects. �However, it is well known that infection is frequently the cause of implant failure.� The aim of this study is to characterize and determine the antibacterial property of a novel calcium phosphate glass in the family CaO-P₂O₅-NaF-MgO-ZnO against Streptococcus mutans. �

Method: Calcium phosphate glasses (CPG) with and without Zn and/or F were prepared by a melt-quenching method.� XRD, SEM, FTIR, ion-selective electrode, pH meter and ICP-MS were used to characterize the experimental samples.� To determine bacterial inhibition, 0.01g and 0.05g of bioactive glass, CPG+Zn, CPG+F, and CPG+Zn+F, (n = 4) were incubated with S. mutans for 0, 2, 4, and 6 hours.� Serial dilutions were plated in duplicate and colony forming units, CFUs/mL, were determined.� Perioglas", C-CPG, and no material were used as controls.

Result: All CPGs demonstrated comparable or better antibacterial activity compared to the commercial control with substantive killing by 4 hours (Figure 1).� Antibacterial activity was found to be dependent on solid loading, with 0.05g showing a maximum effect.� Interestingly, the bactericidal effect of zinc and fluoride ions was greatest when they were employed separately in the compositions. �CPG co-doped with zinc and fluoride ions (CPG+Zn+F) demonstrated higher crystallinity, lower solubility, and thus lower killing.

Conclusion: This family of CPGs, which has previously been shown to have good bone regrowth in vivo, is now demonstrated to have superior bactericidal properties when compared to a commercial control.� The combination of these two characteristics makes this material an attractive candidate for bone regeneration.

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Fig. 1: Concentration dependent bactericidal activity of CPGs