Cytotoxicity Citotoxicity of Dental Materials by the MTT Assay and Nitric Oxide Production: Description of a Technique

Abstract

Introduction: Biocompatibility is one the issues of dental materials, since very few of them are completely inert from the biological standpoint. Therefore, the materials to be used in contact with human tissues should be previously tested in order to simulate possible biological reactions and help understanding the obtained responses. In vitro studies constitute the first stage of these tests. The International Organization for Standardization (ISO) and the American Dental Association’s Council on Dental Materials, Instruments and Equipment advise the use of a set of in vivo and in vitro tests to study the biocompatibility of dental materials and, according to their regulations, biocompatibility tests constitute the main category of these tests. The MTT assay is one of the most commonly used tests for evaluating the cytotoxicity of materials from different origins on cell cultures. Cytotoxicity may also be related to the molecules released due to a certain stimulus, which may cause damage to the biologic tissues. Studies have pointed to the presence of nitric oxide as a molecule with cytotoxic potential on the oral tissues and have indicated its involvement in inflammatory diseases. Objective: To present a methodology for assessing the cytotoxicity of dental materials by the MTT assay and the analysis of nitric oxide production, which is related to the materials’ action on the induction of inflammatory responses. Conclusion: This methodology shows that the MTT assay can be easily adapted for testing cytotoxicity of materials with different compositions, and that the measurement of nitric oxide production by the Griess method provides additional data for cytotoxicity analysis.