Silane Coupling Agent — MFDS Part 1 MCQ
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Correct answer: B — To form an interfacial bond between the inorganic filler and the organic resin matrix
The correct answer is B. Silane is a bifunctional coupling agent at the filler–matrix interface. Its silane end reacts with hydroxyl groups on silica-containing glass or ceramic filler surfaces, forming siloxane bonds, while its organic methacrylate group copolymerises with the resin matrix. This transfers stress across the interface and supports the composite's mechanical integrity. Polymerisation is initiated by an initiator system such as camphorquinone with a co-initiator, not by the silane. Inhibitors such as butylated hydroxytoluene limit premature polymerisation. Fluoride release depends on fluoride-containing filler phases, while polymerisation shrinkage is principally influenced by monomer chemistry, conversion and filler loading rather than being directly prevented by the silane.
Reference: Antonucci JM, Dickens SH, Fowler BO, et al. Chemistry of Silanes: Interfaces in Dental Polymers and Composites. Journal of Research of the National Institute of Standards and Technology. 2005;110(5):541-558. https://pubmed.ncbi.nlm.nih.gov/27308178/