BioPure Article Summary Cytotoxicity of MTAD

BioPure™ MTAD™ Antibacterial Root Canal Cleanser Scientific Study Summary

Evaluation of Cytotoxicity of MTAD Using the MTT-Tetrazolium Method

Entire study published in the Journal of Endodontics
Vol. 29, No. 10, October 2003, Wu Zhang, MD, Mahmoud Torabinejad, DMD, MSD, PhD, and Yiming Li, DDS, MSD, PhD

Overview
It has been recognized for many years that current methods of root canal instrumentation produces a smear layer that covers the surfaces of prepared canal walls. The smear layer contains inorganic and organic substances that include fragments of odontoblastic processes, microorganisms and necrotic materials. Complete debridement of the root canal system with the use of appropriate irrigant and medication reduces the number of microorganisms and increases chances for successful root canal therapy.

Previous studies have shown that MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) is an effective antibacterial irrigant as a final rinse to remove the smear layer from the instrumented surface of root canals. In another study, the ability of MTAD to disinfect contaminated root canals with whole saliva was compare to the effectiveness of NaOCl. Based on their results, it seems that MTAD is significantly more effective than 5.25% NaOCl in eradicating bacteria from infected root canals.

Because root canal irrigants and medications can come in contact with periradicular tissues, in addition to having good antibacterial ability, they also should be biocompatible. Therefore, in choosing irrigants or medications during root canal treatment, biocompatibility should be a major consideration. An ideal root canal irrigant would have strong antibacterial properties and minimal cytotoxic effects on the host tissues.

Purpose
The purpose of this investigation was to test the cytotoxicity of MTAD compared with that of commonly used irrigants and medications.

Materials and Methods
The test materials used in this study were eugenol, 3% hydrogen peroxide, 5.25% NaOCl, REDTA Aqueous Irrigant, Peridex, Pulpdent paste, and MTAD, which contains doxycycline, citric acid and Tween 80. Four concentrations of NaOCl (5.25%, 2.63%, 1.31% and 0.66%) were evaluated for cytotoxicity. Each experiment was conducted using six cultures for each group.

L929 fibroblasts were grown on cell culture plates and were placed in contact with various concentrations of test irrigants and medications. The cytotoxicity of these materials was evaluated 24 hours after incubation using MTT assay. Means and standard deviations of absorbance were calculated for each group and statistically analyzed to determine the presence or absence of significant differences between the means. The 50% inhibitory dose values were calculated, ranked, and statistically analyzed using the sign confidence interval for median.

Conclusion
Based on the test results, it seems that MTAD is less cytotoxic than eugenol, 3% H2O2, Ca(OH)2 paste, 5.25% NaOCl, Peridex, and EDTA. The results show MTAD is more cytotoxic than 2.63%, 1.31%, and 0.66% NaOCl.