Objective: The adhesiveness and water resistance of glass treated with a silane coupling agents containing a long-chain alkyl group were examined.
Methods: Three types of silane coupling agents were used: γ-methacryloyloxypropyltrimethoxysilane (3-MPS), γ-methacryloyloxymethyltrimethoxysilane (1-MMS) and γ-methacryloyloxyoctyltrimethoxysilane (8-MOS). Glass surfaces were treated with the coupling agent, heat-treated, and bonded with resin composite. The specimens were then stored under various conditions: room temperature for one day, in deionized water at 37°C for up to 360 days, or thermally cycled for 10,000 times. After storage, the tensile bond strengths in each group (n = 10 each) were determined using Autograph and the values obtained were statistically analyzed.
Results: The tensile bond strength of 3-MPS after 360 days of water storage and exposure to thermal stress was significantly lower than that after storage at room temperature storage for one day. Alternatively, the bond strength values of 8-MOS were not significantly altered after 360 days of water storage or thermal stress, however, they were significantly than those of 3-MPS and 1-MM.
Conclusion: These finding indicate that treatment of the surface with a silane coupling agent comprising a longer alkyl group (8-MOS) may have results in the formation of a highly hydrophobic layer, which maintained the adhesiveness and improved the water resistance even after storage in water and thermal stress.