d e n t a l m a t e r i a l s 2 3 (2 0 0 7) 1276–1282 a v a i l a b l e a t w w w. s c i e n c e ... more d e n t a l m a t e r i a l s 2 3 (2 0 0 7) 1276–1282 a v a i l a b l e a t w w w. s c i e n c e d i r e c t. c o m j o u r n a l h o m e p a g e : a b s t r a c t Objectives. This study evaluated the effect of two different surface conditioning methods on the repair bond strength of a bis-GMA-adduct/bis-EMA/TEGDMA based resin composite after three aging conditions. Methods. Thirty-six composite resin blocks (Esthet X, Dentsply) were prepared (5 mm × 6 mm × 6 mm) and randomly assigned into three groups for aging process: (a) immersion in citric acid (pH 3.0 at 37 • C, 1 week) (CA); (b) boiling in water for 8 h (BW) and (c) thermocycling (×5000, 5–55 • C, dwell time: 30 s) (TC). After aging, the blocks were assigned to one of the following surface conditioning methods: (1) silica coating (30 m SiO x) (CoJet, 3M ESPE) + silane (ESPE-Sil) (CJ), (2) phosphoric acid + adhesive resin (Single Bond, 3M ESPE) (PA). Resin composite (Esthet·X ®) was bonded to the conditioned substrates incrementally and light polymerized. The experimental groups formed were as follows: Gr1:CA + PA; Gr2:CA + CJ; Gr3:BW + PA; Gr4: BW + CJ; Gr5:TC + PA; Gr6: TC + CJ. The specimens were sectioned in two axes (x and y) with a diamond disc under coolant irrigation in order to obtain non-trimmed bar specimens (sticks, 10 mm × 1 mm × 1 mm) with 1 mm 2 of bonding area. The microtensile test was accomplished in a universal testing machine (crosshead speed: 0.5 mm min −1). Results. The means and standard deviations of bond strength (MPa ± S.D.) per group were as follows: Gr1: 25.5 ± 10.3; Gr2: 46.3 ± 10.1; Gr3: 21.7 ± 7.1; Gr4: 52.3 ± 15.1; Gr5: 16.1 ± 5.1; Gr6, 49.6 ± 13.5. The silica coated groups showed significantly higher mean bond values after all three aging conditions (p < 0.0001) (two-way ANOVA and Tukey tests, ˛ = 0.05). The interaction effect revealed significant influence of TC aging on both silica coated and acid etched groups compared to the other aging methods (p < 0.032). Citric acid was the least aggressive aging medium. Significance. Chairside silica coating and silanization provided higher resin–resin bond strength values compared to acid etching with phosphoric acid followed by adhesive resin applications. Thermocycling the composite substrates resulted in the lowest repair bond strength compared to citric acid challenge or boiling in water.
d e n t a l m a t e r i a l s 2 5 (2 0 0 9) 442–451 a v a i l a b l e a t w w w. s c i e n c e d ... more d e n t a l m a t e r i a l s 2 5 (2 0 0 9) 442–451 a v a i l a b l e a t w w w. s c i e n c e d i r e c t. c o m j o u r n a l h o m e p a g e : a b s t r a c t Objectives. The purpose of this study was to investigate the effect of different surface treatments on the bond strength () of repaired, aged resin composites (ARC). Methods. Forty blocks of Filtek Z250 TM (Z2) and Filtek Supreme TM (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 TM), 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 (0.5 mm 2) using a precision grinding machine. The specimens (n = 30) were tested in tension to fracture and the microtensile bond strength () values were calculated (MPa). Data were analyzed using three-way ANOVA/Tukey test (˛ = 0.05) and Weibull statistics. Results. AO and SC produced similar Ra values, which were greater than the value produced by HA. The 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 values, irrespective of the primer (SI, SB or SI + SB) used. Yet, the RC microstructure influenced the mean values, which were greater for Z2 than for SU. The HA should not be used for repairing ARC.
j o u r n a l o f d e n t i s t r y 3 8 (2 0 1 0) 2 9 – 3 8 a b s t r a c t Objectives: To evalua... more j o u r n a l o f d e n t i s t r y 3 8 (2 0 1 0) 2 9 – 3 8 a b s t r a c t Objectives: To evaluate immediate repair bond strengths and failure types of resin composites with and without surface conditioning and characterize the interacting composite surfaces by their surface composition and roughness. Methods: Microhybrid, nanohybrid and nanofilled resin composites were photo-polymer-ized and assigned to four groups: (1) no conditioning (Control), (2) no conditioning, poly-merized against a Mylar strip (Control, with strip), (3) intermediate adhesive resin (IAR) application, and (4) chair-side silica coating, silanization and intermediate resin application (SC). Resin composites, similar as their substrates, were adhered onto the substrates. Shear force was applied to the interface in a universal testing machine and failure types were evaluated under light microscopy. Surface characterization was done by contact angle measurements, X-ray photoelectron spectroscopy, scanning electron and atomic force microscopy. Results: Significant effects of the resin composite type and surface conditioning were observed. Conditioning the composites with their IARs does not result in significant improvements in bond strength compared to the control with strip (bond strengths between 14.5 and 20.0 MPa). SC increased the bond strength in all composites except TE by an average 8.9 MPa, while in all composites the surface roughness increased from 7 to 384 mm. Failure types in this group were exclusively cohesive. Physico-chemical modelling of the composite surfaces showed that the surfaces were dominated by the resin matrix, with a major increase in silica-coverage after SC for all composites. Conclusion: Intermediate adhesive resin conditioning did not improve the composite-to-composite immediate repair strength. Silica coating and silanization followed by its corresponding IAR, strongly increased repair bond strengths and provided exclusively cohesive failures in the substrate in all composites. (H.J. Busscher). a v a i l a b l e a t w w w. s c i e n c e d i r e c t. c o m journal homepage: www.intl.elsevierhealth.com/journals/jden 0300-5712/$ – see front matter #
d e n t a l m a t e r i a l s 2 3 (2 0 0 7) 1276–1282 a v a i l a b l e a t w w w. s c i e n c e ... more d e n t a l m a t e r i a l s 2 3 (2 0 0 7) 1276–1282 a v a i l a b l e a t w w w. s c i e n c e d i r e c t. c o m j o u r n a l h o m e p a g e : a b s t r a c t Objectives. This study evaluated the effect of two different surface conditioning methods on the repair bond strength of a bis-GMA-adduct/bis-EMA/TEGDMA based resin composite after three aging conditions. Methods. Thirty-six composite resin blocks (Esthet X, Dentsply) were prepared (5 mm × 6 mm × 6 mm) and randomly assigned into three groups for aging process: (a) immersion in citric acid (pH 3.0 at 37 • C, 1 week) (CA); (b) boiling in water for 8 h (BW) and (c) thermocycling (×5000, 5–55 • C, dwell time: 30 s) (TC). After aging, the blocks were assigned to one of the following surface conditioning methods: (1) silica coating (30 m SiO x) (CoJet, 3M ESPE) + silane (ESPE-Sil) (CJ), (2) phosphoric acid + adhesive resin (Single Bond, 3M ESPE) (PA). Resin composite (Esthet·X ®) was bonded to the conditioned substrates incrementally and light polymerized. The experimental groups formed were as follows: Gr1:CA + PA; Gr2:CA + CJ; Gr3:BW + PA; Gr4: BW + CJ; Gr5:TC + PA; Gr6: TC + CJ. The specimens were sectioned in two axes (x and y) with a diamond disc under coolant irrigation in order to obtain non-trimmed bar specimens (sticks, 10 mm × 1 mm × 1 mm) with 1 mm 2 of bonding area. The microtensile test was accomplished in a universal testing machine (crosshead speed: 0.5 mm min −1). Results. The means and standard deviations of bond strength (MPa ± S.D.) per group were as follows: Gr1: 25.5 ± 10.3; Gr2: 46.3 ± 10.1; Gr3: 21.7 ± 7.1; Gr4: 52.3 ± 15.1; Gr5: 16.1 ± 5.1; Gr6, 49.6 ± 13.5. The silica coated groups showed significantly higher mean bond values after all three aging conditions (p < 0.0001) (two-way ANOVA and Tukey tests, ˛ = 0.05). The interaction effect revealed significant influence of TC aging on both silica coated and acid etched groups compared to the other aging methods (p < 0.032). Citric acid was the least aggressive aging medium. Significance. Chairside silica coating and silanization provided higher resin–resin bond strength values compared to acid etching with phosphoric acid followed by adhesive resin applications. Thermocycling the composite substrates resulted in the lowest repair bond strength compared to citric acid challenge or boiling in water.
d e n t a l m a t e r i a l s 2 5 (2 0 0 9) 442–451 a v a i l a b l e a t w w w. s c i e n c e d ... more d e n t a l m a t e r i a l s 2 5 (2 0 0 9) 442–451 a v a i l a b l e a t w w w. s c i e n c e d i r e c t. c o m j o u r n a l h o m e p a g e : a b s t r a c t Objectives. The purpose of this study was to investigate the effect of different surface treatments on the bond strength () of repaired, aged resin composites (ARC). Methods. Forty blocks of Filtek Z250 TM (Z2) and Filtek Supreme TM (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 TM), 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 (0.5 mm 2) using a precision grinding machine. The specimens (n = 30) were tested in tension to fracture and the microtensile bond strength () values were calculated (MPa). Data were analyzed using three-way ANOVA/Tukey test (˛ = 0.05) and Weibull statistics. Results. AO and SC produced similar Ra values, which were greater than the value produced by HA. The 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 values, irrespective of the primer (SI, SB or SI + SB) used. Yet, the RC microstructure influenced the mean values, which were greater for Z2 than for SU. The HA should not be used for repairing ARC.
j o u r n a l o f d e n t i s t r y 3 8 (2 0 1 0) 2 9 – 3 8 a b s t r a c t Objectives: To evalua... more j o u r n a l o f d e n t i s t r y 3 8 (2 0 1 0) 2 9 – 3 8 a b s t r a c t Objectives: To evaluate immediate repair bond strengths and failure types of resin composites with and without surface conditioning and characterize the interacting composite surfaces by their surface composition and roughness. Methods: Microhybrid, nanohybrid and nanofilled resin composites were photo-polymer-ized and assigned to four groups: (1) no conditioning (Control), (2) no conditioning, poly-merized against a Mylar strip (Control, with strip), (3) intermediate adhesive resin (IAR) application, and (4) chair-side silica coating, silanization and intermediate resin application (SC). Resin composites, similar as their substrates, were adhered onto the substrates. Shear force was applied to the interface in a universal testing machine and failure types were evaluated under light microscopy. Surface characterization was done by contact angle measurements, X-ray photoelectron spectroscopy, scanning electron and atomic force microscopy. Results: Significant effects of the resin composite type and surface conditioning were observed. Conditioning the composites with their IARs does not result in significant improvements in bond strength compared to the control with strip (bond strengths between 14.5 and 20.0 MPa). SC increased the bond strength in all composites except TE by an average 8.9 MPa, while in all composites the surface roughness increased from 7 to 384 mm. Failure types in this group were exclusively cohesive. Physico-chemical modelling of the composite surfaces showed that the surfaces were dominated by the resin matrix, with a major increase in silica-coverage after SC for all composites. Conclusion: Intermediate adhesive resin conditioning did not improve the composite-to-composite immediate repair strength. Silica coating and silanization followed by its corresponding IAR, strongly increased repair bond strengths and provided exclusively cohesive failures in the substrate in all composites. (H.J. Busscher). a v a i l a b l e a t w w w. s c i e n c e d i r e c t. c o m journal homepage: www.intl.elsevierhealth.com/journals/jden 0300-5712/$ – see front matter #
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