Effect of irrigants and cementum injury on diffusion of hydroxyl ions through the dentinal tubules.
This study measured hydroxyl ion diffusion through dentinal tubules into a bathing solution. Eighty single-canal, instrumented teeth were divided into 8 groups. Control groups 1 and 3 were irrigated with 10 mL 0.9% saline and 10 mL 6% sodium hypochlorite (NaOCl), respectively. Control groups 5 and 7 were irrigated with 3 mL and 1 mL 17% ethylenediaminetetraacetic acid (EDTA) and then 10 mL 6% NaOCl, respectively. Experimental groups 2, 4, 6, and 8 were irrigated as groups 1, 3, 5, and 7, followed by placement of calcium hydroxide (Ca(OH)2) into canals. Bathing solution pH was recorded for 30 days, a cementum defect was made, and then pH was recorded for another 30 days. With a paired difference test, average pH during steady state was statistically different and higher after the defect (P < .001). With Tukey multiple comparisons, post-defect pH for group 6 was found to be significantly greater (P < .01) than in other groups. This study indicated final canal irrigation with 3 mL 17% EDTA and 10 mL 6% NaOCl before Ca(OH)2 placement allowed the greatest hydroxyl ion diffusion to the root surface.
D000704:Analysis of Variance; D003739:Dental Cementum / Q000293:injuries*; D003804:Dentin / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000493:pharmacokinetics*; D012388:Root Canal Irrigants / Q000494:pharmacology*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000494:pharmacology*
D006878:Hydroxides; D012388:Root Canal Irrigants; C031356:hydroxide ion; D004492:Edetic Acid; D012973:Sodium Hypochlorite