Are primary cells or cell lines more relevant when measuring cytotoxicity?

• A. Cell lines
• B. In Vivo tests
• C. Clinical trials
• D. Primary cells

Answer: (D)

Primary cells are more relevant for measuring cytotoxicity because they preserve the actual characteristics of human tissue, including normal metabolic activity, enzyme expression, and cell–cell and cell–matrix interactions. This makes their responses to dental materials a closer reflection of what happens in patients. Immortalized cell lines, on the other hand, are engineered to proliferate indefinitely and often acquire genetic and epigenetic changes. Those changes can alter how they metabolize substances, respond to stress, or react to toxic compounds, so their reactions may not accurately predict human tissue responses.

The upshot is that primary cells provide a more clinically relevant picture of cytotoxicity, especially for dental materials. They do, however, come with challenges like donor variability, limited lifespan, and availability, which is why researchers sometimes use cell lines for screening or to complement primary-cell data.