- The addition of a silane coupling agent in composite resin formulations plays a crucial role in improving the material's overall performance.
- Silane coupling agents function as a molecular bridge between the inorganic filler particles (such as silica or glass) and the organic resin matrix (typically methacrylate-based resins).

- Specifically, the silane chemically bonds to the surface of the filler particles via its silanol groups, while its organofunctional groups co-polymerize with the resin matrix during polymerization.
- This dual affinity enhances the interfacial adhesion between the filler and the resin, which is essential for improving the mechanical properties of the composite, such as strength, wear resistance, and durability.

- Without effective coupling, the filler particles may not integrate well with the resin matrix, potentially leading to poor mechanical integrity and compromised longevity of the restoration. In contrast, silane treatment ensures efficient stress transfer between the phases, providing a more stable and reliable composite material.

Thus, the correct answer is: Option 1: To enhance bonding between filler particles and resin matrix

Reference: Roberson TM, Heymann HO, Swift EJ Jr. Sturdevant’s Art and Science of Operative Dentistry, 7th Edition, Chapter 10 / Page 225