Document Type : Original Article

Authors

1 Department of Endodontics, Torabinejad Dental Research Center, Iranian Academy of Medical Science, Isfahan University of Medical Sciences, Isfahan

2 Department of Endodontics, Islamic Azad University of Khorasgan, Isfahan, Iran

3 Department of Endodontics, Dental Implant Research Center, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Objective: The aim of this study was to compare the substantivity of chlorhexidine (CHX) 
and doxycycline bond to the dentin in diffusion disk method.
Methods: A total of 92 dentin disks were prepared from Bovine’s teeth root. After removing 
cementum and standardizing disks in weight and outer diameter, they were irrigated with 
sodium hypochlorite 2.5%, ethylenediaminetetraacetic acid 17% and sterile saline and 
sterilled in autoclave. Then, the first group (n = 36) were irrigated with chlrohexine 2% and 
the second group (n = 36) with doxycycline 100 mg/mL, each for a period of 10 min. The 
third group (n = 20) was considered as the control group. Samples were divided into four 
subgroups, which after 1 day, 3, 6, and 12 weeks were incubated in plates containing Muller 
Hinton agar broth and Enterococcus faecalis for a period of 48 h at 37°C temperature; then 
the diameter of the zone of inhibition was measured. The antimicrobial effect of irrigating 
solutions without binding to the dentin was also studied using the plate well method. 
One‑way and univariate variance tests as well as Post‑hoc Tukey were used for data analyses.
Findings: The diameter of the zone of inhibition of doxycycline group was significantly 
more than the CHX group from the beginning to the 3rd week (P < 0.005). After 3rd week, 
mean diameter in doxycycline group declined as compared with the CHX group up to 
12th week (P < 0.005). The difference between means in two groups was not significant in 
the 3rd week (P = 0.87).
Conclusion: The results of this study show that CHX and doxycycline show antibacterial 
activity for 12 weeks; although after 3rd week, the substantivity of CHX was significantly 
greater than doxycycline. Both of these irrigants can be used in other pharmacological and 
medical fields whenever a long‑lasting antibacterial action is needed.

Keywords

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