Insight into the Reaction of Alexidine with Sodium Hypochlorite: A Potential Error in Endodontic Treatment

A laboratory investigation on the effect of biguanide- and pyridine-derived antiseptics on the adhesion of resin composites to dentin

Optimal bonding of adhesive restorations to dentin is crucial to prevent microleakage and enhance the survival of root-filled teeth. The aim of this study was to investigate the effect of chlorhexidine (CHX), alexidine (ALX) and octenidine dihydrochloride (OCT) on the bond strength of resin composites to coronal dentin. Human coronal dentin specimens were treated with 2% CHX, 0.1% ALX, 0.1% OCT or saline then restored with traditional or bulk-fill resin composites. The adhesion strength between the resin and dentin was measured using the microtensile bond strength and failure mode was determined using a stereomicroscope. Treatment with ALX and OCT resulted in significantly greater μTBS compared with CHX and saline, irrespective of the resin composite used. Alexidine treatment predominantly resulted in mixed failure, while adhesive failures were frequently observed in CHX and saline-treated dentin. In conclusion, final irrigation with ALX or OCT improved the bonding of resin composites to dentin.

The Interaction of Two Widely Used Endodontic Irrigants, Chlorhexidine and Sodium Hypochlorite, and Its Impact on the Disinfection Protocol during Root Canal Treatment

In recent years, sodium hypochlorite and chlorhexidine digluconate have been the gold standard of irrigation solutions utilized within the disinfection protocol during root canal treatments. Nowadays, it is known that, during chemical disinfection of the root canal, consecutive application of sodium hypochlorite and chlorhexidine digluconate leads to the formation of an orange-brown precipitate. This precipitate is described as being chemically similar to para-chloroaniline, which is suspected to have cytotoxic and carcinogenic effects. Concerns also exist regarding its influence on the leakage of root canal fillings, coronal restorations, and tooth discoloration. The purpose of this article is to review the literature on the interaction of sodium hypochlorite and chlorhexidine digluconate on the tooth and its surrounding tissues, and to discuss the effect of the precipitate formed during root canal treatment. We further address options to avoid the formation of the precipitate and describe alternative irrigation solutions that should not interact with sodium hypochlorite or chlorhexidine digluconate.