Surface Tension Comparison of Four Common Root Canal Irrigants and Two New Irrigants Containing Antibiotic

The impact of pH on cytotoxic effects of three root canal irrigants

AIM

Cytotoxicity of root canal irrigants is important due to their close contact with host tissues. This study was to assess the possible impact of pH on cytotoxic effects of MTAD, 17% EDTA, and 2.6% NaOCl on the human gingival fibroblasts using MTT assay.

MATERIALS AND METHODS

Human gingival fibroblasts were exposed to the irrigants and their viability was assessed after 1, 6, and 12 h. The pH of the medium was measured in each interval. Light absorption values were measured for each culture medium using Elisa Reader device.

RESULTS

NaOCl had significantly less cytotoxicity than EDTA and MTAD. Also irrigants cytotoxicity decreased in 12, 1, and 6 h, respectively.

CONCLUSION

It seems that variation of the pH resulted in variation in the cytotoxicity of solutions; i.e., it follows the pattern of the pH variation.

Correlation between sealer penetration and microleakage following the use of MTAD as a final irrigant

The relationship between sealer penetration and apical microleakage following the use of MTAD as an irrigant in root canal procedures was evaluated. A collection of 120 human teeth was divided into three groups of 40 in each group. The final rinse was varied as follows: group 1 - the final rinse was saline solution, group 2 - ethylene diamine tetraacetic acid and for group 3 - MTAD. Each group was then divided into two subgroups (20 teeth) and filled with gutta percha and either AH Plus or Dorifill sealer. Half of the teeth were selected for dye penetration testing and the sealer penetration in the remaining teeth was evaluated using scanning electron microscope. There were no significant differences between the three irrigants, but there was less dye penetration in teeth sealed with AH Plus than Dorifill. Penetration of the sealer was better in the MTAD and ethylene diamine tetraacetic acid groups than in the saline group. Statistically, there was no significant difference between the sealer penetration into the dentinal tubules and the dye penetration.

Antimicrobial activity of maleic acid and combinations of cetrimide with chelating agents against Enterococcus faecalis biofilm

INTRODUCTION

Chelating agents, such as EDTA or citric acid, can be incorporated into irrigants in order to provide different properties in a single compound. Maleic acid has recently been proposed as an alternative irrigant to EDTA given its better smear layer removal and biocompatibility; however, its antimicrobial activity is not known. The purpose of the present study was therefore to evaluate the in vitro capacity of maleic acid in eradicating Enterococcus faecalis biofilms and to evaluate the combinations of cetrimide with maleic acid, citric acid, and EDTA.

METHODS

E. faecalis biofilms were grown in the MBEC high-throughput device (Innovotech; Edmonton, Alberta, Canada) for 24 hours and exposed to the irrigating solutions for 30 seconds and 1 and 2 minutes. "Eradication" was defined as 100% bacterial kill. The Student t test was used to compare the efficacy of the irrigant combinations.

RESULTS

Maleic acid eradicated E. faecalis biofilms at a concentration of 0.88% after 30 seconds and at 0.11% after 2 minutes of contact time. When combined with 0.2% cetrimide, it eradicated the biofilms at all three times of exposure. The combination of 0.2% cetrimide with either 15% EDTA or 15% citric acid gave 100% bacterial kill after one minute of contact with the biofilms.

CONCLUSIONS

Maleic acid showed antimicrobial activity against E. faecalis biofilm both alone or in association with cetrimide from 30 seconds onward and the combination of EDTA and citric acid with cetrimide eradicated biofilm after 1 minute of contact.

Irrigation in endodontics

The success of endodontic treatment depends on the eradication of microbes from the root-canal system and prevention of reinfection. The root canal is shaped with hand and rotary instruments under constant irrigation to remove the inflamed and necrotic tissue, microbes/biofilms, and other debris from the root-canal space. Irrigants have traditionally been delivered into the root-canal space using syringes and metal needles of different size and tip design. Clinical experience and research have shown, however, that this classic approach typically results in ineffective irrigation. Many of the compounds used for irrigation have been chemically modified and several mechanical devices have been developed to improve the penetration and effectiveness of irrigation. This article summarizes the chemistry, biology, and procedures for safe and efficient irrigation and provides cutting-edge information on the most recent developments.

Calcium Loss From Root Canal Dentin Following EDTA, EGTA, EDTAC, and Tetracycline-HCl Treatment With or Without Subsequent NaOCl Irrigation

The aim of this study was to determine the extent of calcium removal on root canal dentin after 17% EDTA, 17% EGTA, 15% EDTAC, and 1% tetracycline-HCl treatment; with or without subsequent use of 2.5% NaOCl. Extracted single-rooted human teeth were bisected longitudinally and the root halves (n=100) were isolated with nail varnish, leaving the root canal exposed. The samples were immersed in the test solutions for 1 and 5 minutes, after which the amount of calcium ion (Ca(2+)) release into the solutions was determined by flame photometry. Regardless of treatment time, all single (treatment solution only) and combined (treatment solution with subsequent NaOCl application) irrigation regimens removed significantly more Ca(2+) than control treatment (distilled water). Compared with other groups, treatment with 17% EDTA and 17% EDTA + 2.5% NaOCl resulted in the maximum amount of Ca(2+) removal from root canal dentin (p<0.05). All combined-treatment groups except 17% EGTA + 2.5% NaOCl removed significantly more Ca(2+) than their single-treatment versions (p<0.05). Within each test group, extending the treatment time to 5 minutes resulted in significantly more Ca(2+) removal (p<0.05).