The fluoride release, which is for _____ in vivo, causes ______ in vitro.

• A. pulp irritation; inflammation
• B. caries inhibition; cytotoxicity
• C. caries inhibition; remineralization
• D. osseous growth; necrosis

Answer: (B)

The key idea is that fluoride release from restorative materials has a dual behavior: it provides protection against decay in the mouth, but can be cytotoxic to cells in a laboratory setting. In vivo, fluoride helps inhibit caries by promoting remineralization and reducing demineralization of enamel, which is why it’s described as caries inhibition. When the same material is tested in vitro, the fluoride that leaches out can reach concentrations that harm cells, leading to cytotoxicity. That’s why the pairing caries inhibition in vivo with cytotoxicity in vitro best fits the observed effects. The other options don’t match this pattern: fluoride isn’t primarily linked to pulp irritation with inflammation, osseous growth with necrosis, or a direct in vitro remineralization effect.