Comparison of tissue solubility of human umbilical cord by sodium hypochlrorite and calcium hydroxide

Introduction: As biomechanical preparation of root canal system is not always completely accomplished because of morphological and physical barriers, to obtain a sterile root canal for the success of endodontic treatment, use of chemical solvents is essential. The aim of this in vitro study was to compare effects of Ca (OH)2 and NaOCl in single and combination usage for this purpose. Methods and Materials: In this experimental study, five groups of 40 pieces of human umbilical cord samples were placed in 10 ml of different solvents for 1 wk. The weight of samples was adjusted to 0.03 g. Experimental solvents included: 1) Calcium hydroxide solution (0.6g per ml), 2) 0.5% sodium hypochlorite, 3) 5% sodium hypochlorite, and 4) calcium hydroxide solution for 1 wk and then 0.5% sodium hypochlorite for 30 min, 5) Normal saline. Tissue solubility of these solvents was compared by weight changes of samples after 1 wk. Data was analyzed with Kruscal- wallis and t- student tests. Results: There was no significant difference between calcium hydroxide (Group 1) and salin (Group 5). Other groups had significant differences (p value < 0.01). Conclusion: According to findings of this study, tissue solubilizing of 0.5% NaOCl is less than 5% although both have more solubilizing power than Ca (OH)2. Pretreatment with Ca (OH)2 could not enhance the tissue dissolving effect of 0.5% NaOCl. Key words: Root canal therapy- Irrigators- Sodium hypochlorite- Calcium hydroxide- Tissue solubility