Elsevier

Journal of Endodontics

Volume 34, Issue 3, March 2008, Pages 288-290
Journal of Endodontics

Basic research—biology
The Substitution of Chlorhexidine for Doxycycline in MTAD: The Antibacterial Efficacy Against a Strain of Enterococcus faecalis

https://doi.org/10.1016/j.joen.2007.12.012Get rights and content

Abstract

The antimicrobial effect of MTAD has been largely attributed to the presence of doxycycline. In the present study, chlorhexidine was added to or substituted for doxycycline to compare these three formulations in their ability to disinfect extracted human teeth infected with Enterococcus faecalis. Ten teeth were used in each group along with positive and negative controls. The teeth were treated according to previously published protocols. None of the samples treated with MTAD or MTAD + chlorhexidine showed the presence of residual bacteria. In contrast, 7 of 10 samples treated with MCAD (chlorhexidine substituted for doxycycline) showed positive cultures of E. faecalis. The results clearly showed that although the addition of chlorhexidine did not negatively impact the efficacy of MTAD, the substitution of this antimicrobial agent for doxycycline significantly reduces the efficacy of the solution.

Section snippets

Materials and Methods

Fifty single-rooted human anterior teeth (excluding mandibular incisors) were used in this study. The teeth had been stored in gauze soaked with water to prevent dehydration before use. Each tooth was radiographed to confirm the presence of a patent canal. An access opening was prepared on the lingual or occlusal surface of each tooth to expose the root canal system. After removal of the pulp with a barbed broach and irrigation with distilled water, each tooth was then sterilized by using an

Results

All samples in the positive control group showed the presence of turbidity in the test tubes, whereas all of the negative control samples remained free of growth. None of the 10 samples in groups A and C showed any growth after 1 week of incubation. Seven out of 10 samples in group B showed turbidity in the test tubes. The results are summarized in Table 1.

There was a statistical difference between the four experimental groups. The irrigants used in groups A and C were significantly more

Discussion

In the present study, the controls showed that the test bacteria remained viable during the experimental period and contamination did not occur during the sampling protocol. Evaluation of the bacteria using standard microbiological techniques verified the existence of a pure culture.

MTAD and MTAD-C (MTAD with the addition of 0.2% CHX) both disinfected all 10 teeth in group A and group C, respectively. In contrast, MCAD completely eliminated E. faecalis from only 3 of 10 teeth in group B. These

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The authors acknowledge that, as an institution, Loma Linda University retains a financial interest in this product.

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