Composite Inhibitor — MFDS Part 1 MCQ
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Correct answer: A — To inhibit premature free-radical polymerisation before clinical light activation
BHT is a phenolic free-radical scavenger incorporated at low concentration to inhibit unintended polymerisation of the resin before deliberate photoactivation. This improves storage stability and also helps preserve handling time when the material is exposed to low-intensity ambient light. It does not increase the degree of conversion; excessive inhibitor concentrations may instead reduce conversion or slow polymerisation. Although BHT has antioxidant properties, prevention of restoration discolouration is not its principal role in composite formulation. Filler–resin bonding is produced by a coupling agent, usually an organosilane. Fluoride release depends on fluoride-containing reactive fillers or other fluoride-bearing components, not BHT.
Reference: Kim S et al. Synthetic phenolic antioxidants, including butylated hydroxytoluene (BHT), in resin-based dental sealants. Dental Materials. 2016. https://pubmed.ncbi.nlm.nih.gov/27522571/