Which parameter is most directly assessed in cytotoxicity tests for dental materials?

• A. It measures cell death caused by exposure to the material
• B. It determines color stability
• C. It evaluates wear resistance
• D. It assesses radiopacity

Answer: (A)

Cytotoxicity testing focuses on how a material affects living cells. The parameter directly assessed is cell viability after exposure to the material or its extracts, which shows how many cells survive versus die and thus indicates the material’s toxic potential. This is the core readout of cytotoxicity, linking any leached substances from the material to cellular health.

Color stability, wear resistance, and radiopacity address aesthetics, mechanical durability, and imaging visibility, respectively, and do not measure how the material interacts with cells. In practice, researchers use viability assays (like MTT/XTT or LDH release) to quantify the cytotoxic effect, making cell death or reduced viability the central focus of cytotoxicity tests.