pH changes and calcium ion diffusion from calcium hydroxide dressing materials through root dentin

The purpose of this study was to evaluate Ca2+ and OH- diffusion properties through root dentin by using different calcium hydroxide (CH) dressing mat erials. Twenty-eight single-rooted teeth were instrumented and external def ects were created on the root surface. 17% EDTA was used to eliminate the s mear layer. All surfaces except the external defects were sealed, and the t eeth were placed in normal saline. Ca2+ concentrations and the pH in the sa line were determined for 3 days as the control period. After removing the t eeth from normal saline, they were filled with: (i) DT Temporary Dressing C H; (ii) CH powder and normal saline; (iii) TempCanal; and (iv) CH points. T he teeth were then placed in normal saline, and Ca2+ concentrations and pH values were measured at 1, 3, 7, 14, and 28 days. Nonsetting CH pastes grad ually released Ca2+, whereas this increase was absent from CH points. None of the test materials induced a pH increase in the media during the observa tion period. This study demonstrated that, when nonsetting CH pastes are ap plied to the root canal, diffusion of Ca2+ without an increase in pH to the surrounding media occurs. This implies that these type of material are mov e suitable than CH points for treatment of external root resorption.