Antibacterial Activity of Remineralizing Paste Incorporating Strontium Doped Nano Hydroxyapatite (Sr-nHAp) - A Comparative Study.

Background: The antimicrobial activity was assessed on the basis of the zone of inhibition at different concentrations of strontium doped nano hydroxyapatite and comparing the same with that of Ampicillin.

Aims: The aim of the study was to assess the antimicrobial activity of Strontium doped nano hydroxyapatite (Sr-nHAp) when used as remineralizing agent and the property was compared with the similar effects of Ampicillin.

Methods and material: To focus on the antibacterial properties of Sr-nHAp, bacterial culture was performed in a specialized medium and the antibacterial effectiveness was compared with that of the antimicrobial effect of Ampicillin. The pathogenic culture of Streptococcus mutans and Escherichia coli ( E. coli ) were grown in Brain Heart Infusion media for 24 h at 37°C. Two separate culture plates were assigned for S.mutans and E. coli , each were incorporated with different concentrations of Sr-nHAp and Ampicillin (1 mg/mL). The zone of inhibition around the area inoculated with Sr-nHAp in both S.mutans and E. coli culture plates were assessed and compared with that of Ampicillin.

Statistical analysis: Data was analyzed using the statistical package SPSS 26.0 (SPSS Inc., Chicago, IL) and level of significance was set at P < 0.05.

Results and conclusions: The results of the study proved that there is significant difference in zone of inhibition at 10%, 20% and 30% of Sr-nHAp ( P < 0.05). The antimicrobial activity of Sr-nHAp improves as the concentration increases. It was concluded that 30% Sr-nHAp has shown antimicrobial activity similar to Ampicillin against both S. mutans and E-Coli.