Effectiveness of NaOCl alone or in combination with EDTA on the diffusion of hydroxyl ions released by calcium hydroxide paste

Abstract

Aim:To evaluate the effect of different irrigant solutions employed during removal and replacement of calcium hydroxide paste on the diffusion of hydroxyl ions through root canal dentine in vitro.Methodology:Thirty-five maxillary and mandibular human canines with straight and fully developed roots were used. After mechanical preparation up to 1mm short of tooth length, 30 canals were filled with calcium hydroxide paste and 5 canals were left empty; all teeth had their coronal accesses properly sealed. Teeth were placed in plastic containers with distilled water, and pH was read after 30 days when the paste from 20 teeth was renewed. After removal of the paste by endodontic instrumentation and irrigation with distilled water, canals were replenished with newly mixed paste in Group 1 and 2. In these groups, final irrigation was conducted with 5 mL of EDTA followed by 5 mL of NaOCl in specimens in Group 1, and 5 mL of NaOCl only in specimens in Group 2. In 10 teeth the paste was not replenished at 30 days (Group 3). All specimens were returned to the containers with fresh distilled water, and the pH was recorded after another 30 days. The differences between the first (30d) and second (60d) pH readings were calculated and submitted to analysis of variance and individual comparisons using the Scheffeé's test.Results:Results of mean analysis on differences of pH readings showed that greater diffusion had occurred on specimens in Group 3. Individual comparisons using Scheffeé's test showed statistical significance between Groups 2 and 3, and equivalence between all other groups.Conclusion:It was concluded that the use of EDTA did not enhance diffusion of hydroxyl ions through root canal dentine.

Endodontic re‐instrumentation enhances hydroxyl ion diffusion through radicular dentine

“…Considering that the presence of root cementum could hinder or even prevent ionic diffusion (Tronstad et al 1981, Tao et al 1991, Nerwich et al 1993, this tissue was removed to allow for a better analysis of the diffusion phenomena. The optical microscope analysis showed that the procedure performed for this purpose, which was reported in previous studies (Felippe 1998, Felippe et al 2006, was successful (Fig. 2).…”

“…The optical microscope analysis showed that the procedure performed for this purpose, which was reported in previous studies (Felippe , Felippe et al . ), was successful (Fig. ).…”

“…, Felippe , Felippe et al . ). Although the teeth and the canals had been washed with distilled water, the possibility that sodium hypochlorite solution, CH paste and root canal filling residues increased the pH cannot be excluded (Morfis et al .…”

Effect of passive ultrasonic irrigation on diffusion of hydroxyl ion through radicular dentine

“…2067, KG Sorensen, São Paulo, Brazil) and periodontal curettes [22,23]. Each tooth was immersed in 17 % EDTA and 1 % NaOCl for 3 min each to remove the cemental smear layer.…”

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

“…In the presence of water, calcium hydroxide breaks down into hydroxyl ions (OHˉ) and calcium ions (Ca 2+ ), which are responsible for its therapeutic action. Diffusion of OHˉ raises the pH 7,13) , destroying bacteria and inactivating their enzymes, while that of Ca 2+ reduces osteoclastic activity and activates alkaline phosphatase, which is involved in tissue re-mineralization 4) . A 17% EDTA solution is a common choice in treating root canals in primary teeth 1,11) .…”