Cytotoxicity of substances leached or dissolved from pulp capping materials

AIM: To evaluate the cytotoxic effects of substances leached or dissolved from pulp capping materials on human pulp fibroblasts. METHODOLOGY: The substances were applied to cell cultures in conditioned media. The experimental groups were: GI (control; n = 24)--cultures treated with fresh medium; GII (n = 24)--cultures treated with calcium hydroxide cement; GIII (n = 24)--cultures treated with adhesive resin and GIV (n = 24)--cultures treated with 37% orthophosphoric acid. The media were conditioned by placing the crude materials in contact with fresh culture medium for 1 h. The cytotoxicity analysis was performed using the Trypan blue dye exclusion assay at times of 0, 6, 12 and 24 h for cell viability assay, and at 1, 3, 5 and 7 days for survival assay. Data were treated by anova (P < 0.05) and Tukey's test (P < 0.05). RESULTS: GI and II presented similar cell viability and cell growth. GIII and IV exhibited statistically significant lower percentages of cell viability: GIV only at the 0 h experimental time, whereas in GIII this viability markedly diminished reaching values of 10% by 12 h. Cell growth was impaired only in cultures of GIII. CONCLUSIONS: Substances dissolved from the adhesive system tested were cytotoxic for human dental pulp fibroblasts in culture, whilst substances leached from calcium hydroxide were biocompatible.