Application of high-performance liquid chromatography (HPLC) to quantify formaldehyde release from the chemical interaction of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA)

For more than a century, sodium hypochlorite (NaOCl) 1-5.25% w/v remains universally adopted and extensively regarded as gold standard for irrigation and chemical disinfection of the root canal system (1). However, there is no general consensus regarding the optimal concentration for efficient and safe use (2). The sole use of NaOCl allows for the removal of the organic biomass of the smear layer only, hence the use of a demineralizing, chelating agent such as 17% w/v ethylenediaminetetraacetic acid (EDTA) is recommended for the chelation and removal of the inorganic content of the smear layer (3).