Differential aggressiveness of ethylenediamine tetraacetic acid in causing canal wall erosion in the presence of sodium hypochlorite

Mai, Sui; Kim, Young Kyung; Arola, Dwayne D.; Gu, Li-sha; Kim, Jong Ryul; Pashley, David H.; Tay, Franklin R.

doi:10.1016/j.jdent.2009.10.004

« Previous Next »Journal of Dentistry
Volume 38, Issue 3 , Pages 201-206, March 2010

Differential aggressiveness of ethylenediamine tetraacetic acid in causing canal wall erosion in the presence of sodium hypochlorite

Sui Mai
- Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
Young Kyung Kim
- Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
Dwayne D. Arola
- Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD, USA
Li-sha Gu
- Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
Jong Ryul Kim
- Department of Conservative Dentistry, School of Dentistry, KyungHee University, Seoul, Republic of Korea
David H. Pashley
- Department of Oral Biology, School of Dentistry, Medical College of Georgia, Augusta, GA, USA
Franklin R. Tay
- Department of Endodontics, School of Dentistry, Medical College of Georgia, Augusta, GA 30912-1129, USA
- Corresponding author. Tel.: +1 706 7212031; fax: +1 706 7216252.

Received 7 August 2009; received in revised form 13 October 2009; accepted 13 October 2009. published online 22 October 2009.

Abstract

Objective

This study tested the hypothesis that the use of ethylenediamine tetraacetic acid (EDTA) as a final irrigant causes canal wall erosion only after prolonged use of 5.25% sodium hypochlorite (NaOCl) as the initial irrigant.

Methods

Two irrigation protocols were employed: (1) 5.25% NaOCl as the initial irrigant for 10min and 17% EDTA as the final irrigant for 2min; and (2) 5.25% NaOCl for 60min and 17% EDTA for 2min. Flexural strengths of dentine beams prepared from human mid-coronal dentine were evaluated using a miniature three-point bending device after they were irrigated with either protocol. Transmission electron microscopy was used to examine the conditions of instrumented canal walls irrigated with either protocol after they were bonded with methacrylate resin-based sealers.

Results

Immersion of dentine beams in NaOCl for 60min instead of 10min prior to the use of EDTA resulted in a significant (p<0.001) decline in flexural strength. For both NaOCl initial rinsing times, a 2-min final irrigation with EDTA created similar 0.5μm thick demineralisation fronts. However, extensive surface and subsurface erosion of radicular dentine was seen only when the dentine was immersed in NaOCl for 60min.

Conclusion

The apparent aggressiveness of EDTA in causing canal wall erosion is attributed to the prolonged use of NaOCl. The associated decline in dentine flexural strength has potential clinical relevance when thin pulp chamber dentine is immersed in NaOCl for lengthy periods during canal instrumentation. This may render root-treated teeth more prone to vertical fracture.

Keywords: Dentine, EDTA, Erosion, Flexural strength, Irrigation, NaOCl