Chelating agents in root canal treatment: mode of action and indications for their use : a review.

By Hülsmann M, Heckendorff M, Lennon Á.

Date: 11/2004
Journal: JOE

Summary: 

•Purpose: review the literature on chelating agents, the chemical and pharmacological properties of EDTA preparations and recommendations for their clinical use.

Most highlighted Results: 

1.Chelators were first introduced to endodontics by Nygaard-Òstby (1957). 2. A detergent was added in order to increase the cleaning & bactericidal potential, the new composition EDTAC.

3.In 1969, Stewart et al. presented  RC-Prep paste-type chelating agent. 10%urea peroxide,15%EDTA & glycol. Chelator preparations have been advocated frequently especially in narrow /calcified canals and for removal of smear layer. All manufacturers of NiTi recommend its use during rotary canal preparation to reduce risk of instrument separation.

4.Chelators cause decalcification of dentin. The effectiveness depends more on the application time than the specific product chosen and clearly decreases from the canal orifice towards the apex..

5.Severe erosions after 10 min irrigation with a liquid EDTA chelator (17%), whereas a 1-min exposure was effective in removing the smear layer (CËalt & Serper 2002). Irrigation with a 17% EDTA solution has a good cleaning effect on the root canal walls.

6.Comparing sequences of irrigation, the sequence EDTAC > NaOCl > EDTAC proved to be more efficient in smear layer removal than the sequence NaOCl > EDTAC > NaOCl (Abbott et al. 1991).

7.The antibacterial effect of chelator is low, and it should not replace NaOCl as a standard irrigant. They may improve the ability of NaOCl to penetrate into the dentin and increase its antibacterial effect. EDTA pretreatment may reduce bond strength of adhesive materials and obturation materials.

8.There is no evidence for a bleaching effect when using EDTA preparations containing urea peroxide.