Evaluation of cytotoxicity and pH changes generated by various dental pulp capping materials - an in vitro study.

INTRODUCTION: Various materials are used in direct dental pulp capping method. Their biocompatibility and alkalizing abilities are of primary importance affecting therapeutic effects. The aim of this study was to evaluate and compare the cytotoxicity of various pulp-capping materials on human gingival fibroblasts and investigate the pH changes induced by these materials.

MATERIAL AND METHODS: Human gingival fibroblasts were cultured with nine direct pulp materials using culture plate inserts. The cytotoxic effects were recorded by using an MTT-based colorimetric assay after 3 and 24 h. In the second part of the experiment, the materials were inserted in dialysis tubes and transferred into plastic vials containing deionized water. The changes of the medium pH were measured after 3 and 24 h.

RESULTS: We showed differences in cell viability of gingival fibroblasts after varied time of exposition for the tested materials. Cell viability after 24 h increased for Dycal, Biopulp, and Calcipro, and decreased for Calcipulpe, Angelus, Angelus White, and ProRoot Regular. Cell viability for ProRoot and Life did not change. Non-setting calcium hydroxide preparations followed by the MTA group and setting calcium hydroxide materials produced the highest pH. All the tested materials significantly increased pH (p < 0.0001) at 24 h.

CONCLUSIONS: Currently used pulp capping materials varied in their cytotoxicity relative to human gingival fibroblasts and their alkalizing capacities. Since most likely pH does not affect the viability of cultured cells, further investigations are required to determine physicochemical properties of these materials and the biological activity of the dental pulp.