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.

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This study aimed to evaluate the effect of dentin pretreatment on the shear bond strength (SBS) of self-adhesive composite resin (SACR). A flat dentin surface was prepared on the labial aspect of bovine mandibular incisors, and four pretreatment agents were applied to this surface: enamel conditioner (EC; Shofu), cavity conditioner (CC; GC), KATANA cleaner (KC; Kuraray Noritake Dental), and Super Bond C&B Green Activator (GA; Sun Medical). Following each pretreatment, SACR (FIT SA F03 A2; Shofu) was placed to create cylindrical specimens. Control group 1 (Cont-1) received no pretreatment, while control group 2 (Cont-2) was treated with a one-component self-etching adhesive (BeautiBond Xtreme; Shofu) before applying a flowable composite resin (Beautifill Flow Plus X F00 A2; Shofu). After storing the specimens in water at 37.0°C for 24 hours, SBS was measured (n = 10 for each group). The adherend dentin surface was examined using scanning electron microscopy (SEM). The SBS was greatest in Cont-2, followed by Cont-1 and the KC group. The EC, CC, and GA groups showed significantly lower bond strength than Cont-1. SEM observations revealed clear openings of dentin tubules in the EC, CC, and GA groups. These results indicate that the type of pretreatment agent significantly affects the SBS of SACR.

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This study aimed to elucidate the effects of combining fiber-reinforced flowable composite resins for core materials with resin luting agents on the shear bond strength of CAD-CAM composite resin blocks. The core materials tested included everX Flow (GC), Unifilcore EM (GC), Clearfil DCcore Automix ONE (Kuraray Noritake Dental), Esthecore (Tokuyama Dental), and Beautycore LC Injectable (Shofu). Cylindrical specimens of these materials were fabricated and embedded. Plate specimens, 5 mm in thickness, were fabricated from CAD-CAM composite resin blocks. Each resin luting agent was selected from the same manufacturer as the corresponding composite resin for the core material. The adherend surfaces were polished, alumina-blasted, and treated according to the manufacturer’s recommendations before the application and pressing of the resin luting agent. Shear bond strength testing was conducted at a crosshead speed of 1 mm/min (n = 12). The results showed shear bond strengths ranging from 27 to 38 MPa, with significant variations depending on material combinations (p < 0.05). The study concluded that the specific combination of composite resin for core materials and resin luting agents influenced the bond strength with CAD-CAM composite resin blocks.

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