Evaluation of calcium (Ca2+) and hydroxide (OH-) ion diffusion rates of indirect pulp capping materials

The aim of this study was to evaluate and compare the calcium (Ca2+) and hydroxide (OH-) ion release of 4 artificially produced pulp capping materials (MTA, Biodentin, TheraCal LC, Calsimol) used for indirect pulp capping treatment.

In total, 70 freshly extracted human third molar teeth were used for the study. Cavities of extracted teeth were prepared by round burs. The remaining dentin thickness (1 ± 0.3 mm) tissue was measured by a micrometer and cone beam computerized tomography. Indirect pulp capping was performed in the cavities using Calcimol, MTA, TheraCal LC and Biodentin. The leached Ca2+ were measured using optical emission spectrometry and the release of OH- ions using a pH meter. The measurements were performed after 24 hours, 7 days and 28 days in saline solution. Statistical analysis was performed using 1-way and 2-way analysis of variance (ANOVA) tests (p<0.05).

Ca2+ ions were detected in treated saline solution during the experimental period for all materials. All the measurements of Biodentin and Theracal LC levels for Ca2+ ions were higher than those of the other materials (p<0.05). For all materials, Ca2+-ion release increased during the first 7 days followed by a linear decrease during the subsequent study periods. The Biodentine group showed the highest OH- ion rates compared to the other materials in the 24-hour examination period, while the scores gradually decreased during the subsequent measurement periods (p<0.05).

Tricalcium silicate materials such as Biodentine and TheraCal LC used in this study may be preferable for indirect pulp capping because of their stimulation of hard tissue formation and ion-releasing ability.