Which statement best summarizes cytotoxicity testing?

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

Answer: (A)

Cytotoxicity testing evaluates whether a dental material has a toxic effect on living cells, specifically if exposure to the material or its extracts reduces cell viability or causes cell death. In practice, it’s an in vitro screen where cells are exposed to the material or its leachables, and viability is measured with assays that detect metabolic activity or membrane integrity. This type of test helps identify harmful substances released by the material and supports biocompatibility assessments, often guided by standards like ISO 10993-5. It is not about mechanical wear, color changes, or imaging properties, which pertain to wear resistance, color stability, and radiographic density, respectively. So the statement that cytotoxicity testing measures cell death caused by exposure to the material best captures its purpose.