In vitro antimicrobial activity of ZnO based glass-ceramics against pathogenic bacteria.

The antibacterial activity of ZnO (0-15.53 mol%) based SiO2-CaO-P2O5-Na2O-CaF2 bioactive glass-ceramics synthesized by controlled crystallisation were studied against eight micro-organisms using modified Kirby Bauer method. The antibacterial activity of the specimens was statistically evaluated using one-way analysis of variance and P < 0.05 was used as the level of significance. In vitro dissolution tests were performed in stimulated body fluid for 48 h at 37 °C for different time intervals to correlate the dissolution behaviour of test samples with antibacterial effects. The results illustrate that specimen BZn15.53 having the highest concentration of ZnO (15.53 mol%) demonstrated the strongest effect against Staph.aureus, S. epidermidis, B. subtilis and K. pneumonia. The effectiveness of BZn15.53 in inhibiting bacteria was due to accumulation of Zn(+2) ions around the surface of the bacteria cell release that caused the death of the cell, besides the presence of hydroxyapatite phase was also responsible for damaging the cell membrane of bacteria.