Application of 17% EDTA Enhances Diffusion of ⁴⁵Ca-labeled OH⁻ and Ca²⁺ in Primary Tooth Root Canal

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Proper cleaning of the root canal is key to the success of endodontic treatment as it allows more effective diffusion of medication throughout the dentinal tubules. The aim of this in vitro study was to investigate the efficacy of 17% ethylenediaminetetraacetic acid (EDTA) in enhancing diffusion of hydroxyl (OH⁻) and calcium ions (Ca²⁺) throughout the root canal in primary teeth. The canals of 25 primary tooth roots were cleaned with endodontic files and 1% sodium hypochlorite. Three groups (G) were then established: GI, in which final irrigation was performed with 1% sodium hypochlorite; GII, in which 17% EDTA was used; and GIII, in which no irrigation was performed. The roots canals in GI and GII were filled with a calcium hydroxide-based paste labeled with the radioisotope calcium-45. Diffusion of OH⁻ was detected with pH strips and Ca²⁺ analyzed by measuring radioactivity in counts per min. Group II differed statistically from the other groups in diffusion of OH⁻ at 24 hr (p<0.05), but no significant difference among groups was found at the day 7 evaluation; GII also differed statistically from the other groups in diffusion of Ca²⁺ at 24 hr (p<0.05). These results suggest that application of 17% EDTA in primary tooth enhances diffusion of OH⁻ and Ca²⁺.