Abstract:

  Background and Aim: The aim of this study was to evaluate the durability of antibacterial effect of tetracycline in different conditions in microbial culture.

  Materials and Methods : In this experimental study, samples were the roots of extracted teeth of patients with periodontal disease, after removal of calculus and necrotic cementum on the teeth and exposure of dentinal tubules, the roots were shaped with a double-end diamond cutter disc and were kept in autoclave. Then samples were transferred into tetracycline solution with various concentrations and kept there for various periods of time. Each group was then washed in a 20 ml normal saline solution for 10 minutes , 1 week and 2 weeks and was transferred into a bacterial culture to evaluate the diameter of halo which demonstrates inhibitory effect of antibiotic on bacterial growth. The data obtained were analyzed using ANOVA test under spss software.

  Results : The Maximum average of the diameter of the halo that was statistically significant (P value<0.05) in various situations of experiment was 17.5 mm. This which was seen in the teeth that were kept 60(s) in tetracycline solution of 100 mg/ml and also in the groups that were 240(s) in different concentrations of tetracycline and washed 10 minutes by normal saline.

  Conclusion: Adequate anti-bacterial effect was obtained in the group that was placed in tetracycline concentration of 50 mg/ml for 120 (s) and washed for 10 minutes by normal saline.