Effect of calcium hydroxide and sodium hypochlorite in dentin resistance: in vitro study

Introduction: A number of substances used as intracanal dressings have been linked to the weakening of tooth structure, particularly if used for prolonged periods. This study assessed the effect of 5% sodium hypochlorite solution and calcium hydroxide paste in the inorganic composition of the dentin. Methods: Twelve instrumented root canal of monoradicular teeth, divided into four groups of 3 teeth each were sectioned longitudinally into two equal parts after removing the crown. Then, group A was irrigated with sodium hypochlorite and stored in the calcium hydroxide; group B was irrigated with sodium hypochlorite and stored in saline; group C was irrigated with saline solution and stored in saline; group D was irrigated with physiological serum and stored in calcium hydroxide. The teeth were stored for 1 and 3 months and subsequently analyzed by electron microprobe. Results: After the chemical composition analysis, Ca/P ratio are relatively constant. Conclusion: Our results suggest that neither calcium hydroxide nor sodium hypochlorite affected the inorganic component of the teeth, supporting the idea that the main effect of this substances are on the organic part.