Browsing by Subject "Microtensile bond strength"

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    Effect of surface treatments on microtensile bond strength of repaired aged silorane resin composite
    (2010) Palasuk, Jadesada; Platt, Jeffrey A., 1958-; Levon, John A.; Brown, David T.; Hovijitra, Suteera, 1944-; Cho, Sopanis D.
    Background: A silorane based resin composite, Filtek LS restorative, has been introduced to overcome the polymerization shrinkage of the methacrylate based resin composite. The repair of resin composite may hold clinical advantages. Currently, there is no available information regarding the repair potential of silorane resin composite with either silorane or methacrylate based resin composite. Objectives: The purpose of this study was to compare the repaired microtensile bond strength of aged silorane resin composite using different surface treatments and either silorane or methacrylate based resin composite. Methods: One hundred and eight silorane resin composite blocks (Filtek LS) were fabricated and aged by thermocycling between 8oC and 48oC (5000 cycles). A control (solid resin composite) and four surface treatment groups (no treatment, acid treatment, aluminum oxide sandblasting and diamond bur abrasion) were tested. Each treatment group was randomly divided in half and repaired with either silorane resin composite (LS adhesive) or methacrylate based resin composite (Filtek Z250/Single Bond Plus). Specimens were 12 blocks and 108 beams per group. After 24 hours in 37oC distilled water, microtensile bond strength testing was performed using a non-trimming technique. Fracture surfaces were examined using an optical microscopy (20X) to determine failure mode. Data was analyzed using Weibull-distribution survival analysis. Results: Aluminum oxide sandblasting followed by silorane or methacrylate based resin composite and acid treatment with methacrylate based resin composite provided insignificant differences from the control (p>0.05). All other groups were significantly lower than the control. Failure was primarily adhesive in all groups. Conclusion: Aluminum oxide sandblasting produced comparable microtensile bond strength compared to the cohesive strength of silorane resin composite. After aluminum oxide sandblasting, aged silorane resin composite can be repaired with either silorane resin composite with LS system adhesive or methacrylate based resin composite with methacrylate based dentin adhesive.
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    Microtensile bond strength of new paste/paste resin-modified glass ionomer cement systems : the effect of dentin pretreatment
    (2011) Al-Fawaz, Yasser Fawaz, 1983-; Cook, Norman Blaine, 1954-; Hara, Anderson T.; Matis, Bruce A.; Cochran, Michael A. (Michael Alan), 1944-; Bottino, Marco C.
    MICROTENSILE BOND STRENGTH OF NEW PASTE/PASTE RESIN-MODIFIED GLASS IONOMER CEMENT SYSTEMS: THE EFFECT OF DENTIN PRETREATMENT by Yasser Fawaz Al-fawaz Indiana University School of Dentistry Indianapolis, Indiana Background: In order to improve the clinical performance of RMGIC 3M ESPE and GC America introduced paste/paste resin-modified glass ionomer cements, Ketac™ Nano and Fuji Filling™ LC, respectively. Both companies developed non-rinse substrate conditioners (i.e., Ketac Nano Primer-3M ESPE and GC Self-Conditioner-GC America) that should be used with these new materials instead of the conventional polyacrylic acid. It has been also advised by both manufacturer’s to use this novel substrate conditioner with the previously marketed RMGICs. Objective: to investigate whether the use of novel non-rinse conditioners (i.e., Ketac Nano Primer 3M ESPE and GC Self Conditioner GC America) as substrate pre-treatment and the new paste/paste resin-modified glass-ionomer cement, RMGIC (Ketac™ Nano 3M ESPE and Fuji Filling™ LC GC America) would affect the microtensile dentin bond strength (µTBS) of the material when compared to the traditional RMGIC with polyacrylic acid as a surface substrate pre-treatment. Materials and Methods: 96 extracted non-restored human molar were sectioned to expose occlusal dentin. Dentin surface was finished with SiC paper to standardize the smear layer. Bonding protocols of the different materials to dentin were performed following the use of two dentin conditioners. Eight groups (n=12) were tested: G1: Ketac Nano Primer + Ketac Nano, G2: Ketac Conditioner + Ketac Nano, G3: Ketac Nano Primer + Photac Fil, G4: Ketac Conditioner + Photac Fil, G5: GC Self Conditioner + Fuji Filling LC, G6: GC Cavity Conditioner + Fuji Filling LC, G7: GC Self Conditioner + Fuji II LC and G8: GC Cavity Conditioner + Fuji II LC. The specimens were stored in 37°C for 24h in 100% humidity before cutting non-trimmed beams for the µTBS with cross-sectional areas of approximately 0.8 × 0.8 mm2. Nine beams were used from each specimen. Test was done using universal testing machine at a cross-head speed of 1mm/min. Debonded specimens were examined under a stereomicroscope at 45× magnification to evaluate the failure mode. Eight randomly chosen representative debonded beams were imaged under a scanning electron microscope (SEM). Results: µTBS in MPa (mean ± SE) were: G1: 9.5±1.0, G2: 11.0±1.0, G3:20.0±1.0, G4:16.8±0.9, G5: 15.1±1.0, G6: pre-test failure, G7: 20.0±1.0, G8:14.1±0.9. Weibull-distribution survival analysis was used to compare the differences in microtensile peak stress among the groups. Group5 has cohesive predominant faultier mod while the other groups have adhesive predominant failure. Conclusion: Within the limitations of this study, the use of the novel non-rinse conditioners did not improve the microtensile bond strength of new paste/paste RMGIC to dentin. In fact, the use of the novel non-rinse conditioners enhanced the bond strength of the traditional RMGIC to dentin.