OBJECTIVES: The purpose of this study was to investigate the effect of different surface treatments on the bond strength (sigma) of repaired, aged resin composites (ARC). METHODS: Forty blocks of Filtek Z250 (Z2) and Filtek Supreme (SU) were made, stored in deionized water for 9 days, and randomly assigned to different surface treatment groups: hydrofluoric acid etching (HA), abrasion using a coarse diamond bur (AB), sandblasting with alumina particles (AO), and silica coating (SC). The average roughness (Ra) of the treated surfaces was measured with a profilometer. An adhesive system (SB-Adper Single Bond Plus), a silane (SI) or a combination of both (SI+SB) were applied after each surface treatment. The blocks were restored with the same composite (RC) and cut to produce bars that were turned into dumbbell-shaped specimens (0.5mm(2)) using a precision grinding machine. The specimens (n=30) were tested in tension to fracture and the microtensile bond strength (sigma) values were calculated (MPa). Data were analyzed using three-way ANOVA/Tukey test (alpha=0.05) and Weibull statistics. RESULTS: AO and SC produced similar Ra values, which were greater than the value produced by HA. The sigma values were statistically influenced by the type of RC (p<0.0001), by the surface treatment (p<0.0001) and by the surface coating (p<0.0001). Treating the surface of Z2 with SC+SB produced the greatest m value. SIGNIFICANCE: AO and SC produced the greatest sigma values, irrespective of the primer (SI, SB or SI+SB) used. Yet, the RC microstructure influenced the mean sigma values, which were greater for Z2 than for SU. The HA should not be used for repairing ARC.
OBJECTIVES: The purpose of this study was to investigate the effect of different surface treatments on the bond strength (sigma) of repaired, aged resin composites (ARC). METHODS: Forty blocks of Filtek Z250 (Z2) and Filtek Supreme (SU) were made, stored in deionized water for 9 days, and randomly assigned to different surface treatment groups: hydrofluoric acid etching (HA), abrasion using a coarse diamond bur (AB), sandblasting with alumina particles (AO), and silica coating (SC). The average roughness (Ra) of the treated surfaces was measured with a profilometer. An adhesive system (SB-Adper Single Bond Plus), a silane (SI) or a combination of both (SI+SB) were applied after each surface treatment. The blocks were restored with the same composite (RC) and cut to produce bars that were turned into dumbbell-shaped specimens (0.5mm(2)) using a precision grinding machine. The specimens (n=30) were tested in tension to fracture and the microtensile bond strength (sigma) values were calculated (MPa). Data were analyzed using three-way ANOVA/Tukey test (alpha=0.05) and Weibull statistics. RESULTS: AO and SC produced similar Ra values, which were greater than the value produced by HA. The sigma values were statistically influenced by the type of RC (p<0.0001), by the surface treatment (p<0.0001) and by the surface coating (p<0.0001). Treating the surface of Z2 with SC+SB produced the greatest m value. SIGNIFICANCE: AO and SC produced the greatest sigma values, irrespective of the primer (SI, SB or SI+SB) used. Yet, the RC microstructure influenced the mean sigma values, which were greater for Z2 than for SU. The HA should not be used for repairing ARC.
Authors: Giovanni Tommaso Rocca; Ladislav Gregor; Maria Jose Sandoval; Ivo Krejci; Didier Dietschi Journal: Clin Oral Investig Date: 2011-11-09 Impact factor: 3.573
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