Effect of 8-methacryloxyoctyl trimethoxy silane concentration on the bonding performance and durability to zirconia

This study evaluated the bonding performance and durability of a novel long-chain silane, 8-methacryloxyoctyl trimethoxysilane (8-MOTS), on zirconia surfaces. Specimens were treated with varying concentrations of 8-MOTS (0.1-4.0%) and compared with 3-(trimethoxysilyl)propyl methacrylate (3-TMSPMA) and a commercial silane primer. All zirconia surfaces underwent airborne-particle abrasion with alumina to simulate a clinically common surface treatment. Shear bond strength (SBS) was assessed after water storage (37ºC, 24 h) or boiling (100ºC, 16 h) as a severe hydrothermal screening method. The most favorable bonding performance was observed with 8-MOTS at 1.0% and 1.5%, maintaining SBS values ≥20 MPa after boiling. Failure-mode analysis and scanning electron microscopy indicated greater luting-agent retention and more combined failures in high-performing groups. Within the present alumina-abrasion and MDP-containing bonding protocol, 8-MOTS at 1.0-1.5% showed favorable durability.