Abstract:

  Background and Aim: Reports indicate an increase in the resistance of oral bacteria to the antibiotics. This study was conducted with the aim to compare the antibacterial effects of colloidal Nanosilver and Nigella sativa oil.

  Materials and Methods : In this experimental laboratory study, the disk diffusion method was used on 76 samples to evaluate the anti-bacterial properties of Nigella sativa oil extract in concentrations of 330mg/mL (up to 10.312 mg/ mL) and similar properties of Nanosilver in concentrations of 3.125 to 3500ppm.The samples were divided into 2 groups of oral bacteria consisting of Streptococcus mutans and S.sanguis . The results were compared with anti-bacterial effect of the standard disk of amoxicillin (25 µg). The growth medium consisted of Mueller Hinton agar plates in which standard strains of bacteria with 0.5 McFarland concentrations were cultured. The bacterial inhibitory zone of each disk was measured and the data was analyzed using the ANOVA statistical test.

  Results: The Nigella Sativa oil in concentration of 330mg/mL and Nanosilver in concentration of 3500 ppm demonstrated an inhibitory zone of 22-33.5mm respectively for S. mutans and 9.75-11 mm respectively for S.sanguis. The inhibition zone of standard amoxicillin disc (25 µg) was 19.75 – 21.75mm.

  Conclusion: Colloidal Nanosilver showed the highest antibacterial activity against both strains of the bacteria.

  The antibacterial effects of Nigella sativa and amoxicillin were similar on S. mutans whereas, Nigella stavia was found to be more effective than amoxicillin on S.sanguis.