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Influence of etching procedure on pressable and CAD–CAM lithium-disilicate surface
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d e n t a l m a t e r i a l s 3 0 S ( 2 0 1 4 ) e1–e180
76 Influence of etching procedure on pressable and CAD–CAM lithium-disilicate surface
Time
5%
M. Sedda ∗ , R. Fabian Fonzar, M. Carrabba, M. Tricarico, A. Vichi, M. Ferrari University of Siena, Department of Medial Biotechnologies, Siena, Italy Purpose: To evaluate the effect of 5% and 9% hydrofluoric acid at 0, 10, 20, 30, 40, 60, 80, and 120 s application time on pressable and CAD–CAM lithium-disilicate surface. Methods and materials: To obtain the pressable lithiumdisilicate specimens, an acrylate polymer block (IPS-AcrylCAD, Ivoclar Vivadent) was perpendicularly cut with a slow-speed water-cooled diamond saw to obtain bar-shaped specimens with dimensions of 4 mm in width, 1.5 mm in thickness, and 1 mm in length. Sprueing and investing were carried out following manufacturer instructions, as well as pre-heating and pressing (EP-600-Combi, Ivoclar Vivadent). LT A3 ingots were used for pressing specimens (IPS e.max Press, Ivoclar Vivadent). After heat-pressing, rough and fine divesting, reaction layer removal and finishing procedure were performed following manufacturer instructions. Press specimens were randomly assigned to groups 1 and 2. To obtain CAD–CAM specimens, the blocks (IPS e.max CAD, Ivoclar Vivadent) were cut with a slow-speed water-cooled diamond saw to obtain bar-shaped specimens with dimensions of 4 mm in width, 1.5 mm in thickness, and 1 mm in length. CAD–CAM specimens were randomly assigned to groups 3 and 4. Polishing was performed for all groups with 600, 1200 and 2400 grit paper. Groups 1 and 3 were etched with 5% HF, groups 2 and 4 were etched with 9% HF. Hydrofluoric acid application time were: 0, 10, 20, 30, 40, 60, 80, and 120 s. After acid application, specimens were profusely rinsed out with running water and vibrated for 3 min in a 95% alcohol solution using an ultrasonic bath. Roughness analysis (m) was carried out using a roughness-test device. After measurements specimen were processed for SEM Observations. Correlation between mean roughness and etching time was analyzed by the Pearson Correlation Test. Results: A significant positive correlation was found between etching time and final roughness of the specimens in all tested groups (p < 0.001). Both for pressable and CAD–CAM specimens the roughness was higher with the time increased and with more concentrated acid solution. Pressable specimens resulted more sensitive to etching compared to CAD–CAM specimens. Conclusion: Using 9% HF and increasing the etching time produce a surface with higher roughness. Further investigations are needed to verify the influence of the roughness on the bond strength between the lithium-disilicate restoration and the dental tissues.
e.max Press
e.max CAD
9%
5%
9%
Mean S.D. Mean S.D. Mean S.D. Mean 0 10 20 30 40 60 80 120 P. Corr. Sig.
0.02 0.04 0.06 0.07 0.09 0.17 0.21 0.20
0.01 0.02 0.01 0.02 0.01 0.03 0.03 0.02
0.908 <0.001
0.02 0.04 0.08 0.13 0.16 0.25 0.24 0.57
0.01 0.01 0.01 0.01 0.02 0.04 0.01 0.04
0.965 <0.001
0.02 0.04 0.05 0.05 0.05 0.05 0.06 0.08
0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.00
0.852 <0.001
0.02 0.03 0.05 0.06 0.06 0.09 0.09 0.11
S.D. 0.00 0.01 0.01 0.01 0.00 0.01 0.01 0.01
0.944 <0.001
http://dx.doi.org/10.1016/j.dental.2014.08.077 77 Shear bond strength between acrylic resin teeth and composite resin M.A. Basílio ∗ , K.V. Cardoso, G.M.R.M. De Souza, E.M. Mariscal, J.N. Arioli-Filho UNESP – Univ Estadual Paulista, Department of Dental Materials and Prosthodontics, Araraquara, Brazil Purpose: The aim of this study was to evaluate the effects of surface treatments on the shear bond strength of a composite resin (CR) bonded to acrylic denture teeth. Methods and materials: Vestibular surfaces of 56 acrylic resin teeth were flattened using silicon carbide paper (240-grit) for 2 min. Teeth were embedded in auto-polymerized acrylic resin (AR) with the vestibular surfaces exposed to undergo treatments. Artificial teeth were separated into 4 groups (n = 14): (1) methyl-methacrylate (MMA) monomer treatment for 3 min followed by AR insertion on the treated surfaces (positive control); (2) MMA monomer for 3 min followed by CR insertion on the treated surfaces (negative control); (3) A 2:1 mix of CR-AR treatment additional to a previous MMA monomer for 3 min followed by CR insertion on the treated surfaces; (4) A 2:1 mix of CR-AR and a bonding system treatments, respectively, additional to a previous MMA monomer for 3 min followed by CR insertion on the treated surfaces. A cylindrical split mold (5-mm diameter and 2.5-mm length) mounted over the treated surfaces was used to AR and CR materials insertion. After a 21-days period in artificial saliva storage, bond strength was assessed using a shear test device in a universal testing machine (EMIC, model DL 3000) at a crosshead speed of 0.5 mm/min until specimen failure. Data from bond strength assay were normally distributed (Kolmogorov–Smirnov, P = 0.05). One-way ANOVA and Dunnett’s test for multiple comparisons were applied to determine significant differences (P < 0.05). Failure mode was determined using a stereomicroscope (×40).
d e n t a l m a t e r i a l s 3 0 S ( 2 0 1 4 ) e1–e180
76 Influence of etching procedure on pressable and CAD–CAM lithium-disilicate surface
Time
5%
M. Sedda ∗ , R. Fabian Fonzar, M. Carrabba, M. Tricarico, A. Vichi, M. Ferrari University of Siena, Department of Medial Biotechnologies, Siena, Italy Purpose: To evaluate the effect of 5% and 9% hydrofluoric acid at 0, 10, 20, 30, 40, 60, 80, and 120 s application time on pressable and CAD–CAM lithium-disilicate surface. Methods and materials: To obtain the pressable lithiumdisilicate specimens, an acrylate polymer block (IPS-AcrylCAD, Ivoclar Vivadent) was perpendicularly cut with a slow-speed water-cooled diamond saw to obtain bar-shaped specimens with dimensions of 4 mm in width, 1.5 mm in thickness, and 1 mm in length. Sprueing and investing were carried out following manufacturer instructions, as well as pre-heating and pressing (EP-600-Combi, Ivoclar Vivadent). LT A3 ingots were used for pressing specimens (IPS e.max Press, Ivoclar Vivadent). After heat-pressing, rough and fine divesting, reaction layer removal and finishing procedure were performed following manufacturer instructions. Press specimens were randomly assigned to groups 1 and 2. To obtain CAD–CAM specimens, the blocks (IPS e.max CAD, Ivoclar Vivadent) were cut with a slow-speed water-cooled diamond saw to obtain bar-shaped specimens with dimensions of 4 mm in width, 1.5 mm in thickness, and 1 mm in length. CAD–CAM specimens were randomly assigned to groups 3 and 4. Polishing was performed for all groups with 600, 1200 and 2400 grit paper. Groups 1 and 3 were etched with 5% HF, groups 2 and 4 were etched with 9% HF. Hydrofluoric acid application time were: 0, 10, 20, 30, 40, 60, 80, and 120 s. After acid application, specimens were profusely rinsed out with running water and vibrated for 3 min in a 95% alcohol solution using an ultrasonic bath. Roughness analysis (m) was carried out using a roughness-test device. After measurements specimen were processed for SEM Observations. Correlation between mean roughness and etching time was analyzed by the Pearson Correlation Test. Results: A significant positive correlation was found between etching time and final roughness of the specimens in all tested groups (p < 0.001). Both for pressable and CAD–CAM specimens the roughness was higher with the time increased and with more concentrated acid solution. Pressable specimens resulted more sensitive to etching compared to CAD–CAM specimens. Conclusion: Using 9% HF and increasing the etching time produce a surface with higher roughness. Further investigations are needed to verify the influence of the roughness on the bond strength between the lithium-disilicate restoration and the dental tissues.
e.max Press
e.max CAD
9%
5%
9%
Mean S.D. Mean S.D. Mean S.D. Mean 0 10 20 30 40 60 80 120 P. Corr. Sig.
0.02 0.04 0.06 0.07 0.09 0.17 0.21 0.20
0.01 0.02 0.01 0.02 0.01 0.03 0.03 0.02
0.908 <0.001
0.02 0.04 0.08 0.13 0.16 0.25 0.24 0.57
0.01 0.01 0.01 0.01 0.02 0.04 0.01 0.04
0.965 <0.001
0.02 0.04 0.05 0.05 0.05 0.05 0.06 0.08
0.00 0.01 0.01 0.01 0.01 0.01 0.01 0.00
0.852 <0.001
0.02 0.03 0.05 0.06 0.06 0.09 0.09 0.11
S.D. 0.00 0.01 0.01 0.01 0.00 0.01 0.01 0.01
0.944 <0.001
http://dx.doi.org/10.1016/j.dental.2014.08.077 77 Shear bond strength between acrylic resin teeth and composite resin M.A. Basílio ∗ , K.V. Cardoso, G.M.R.M. De Souza, E.M. Mariscal, J.N. Arioli-Filho UNESP – Univ Estadual Paulista, Department of Dental Materials and Prosthodontics, Araraquara, Brazil Purpose: The aim of this study was to evaluate the effects of surface treatments on the shear bond strength of a composite resin (CR) bonded to acrylic denture teeth. Methods and materials: Vestibular surfaces of 56 acrylic resin teeth were flattened using silicon carbide paper (240-grit) for 2 min. Teeth were embedded in auto-polymerized acrylic resin (AR) with the vestibular surfaces exposed to undergo treatments. Artificial teeth were separated into 4 groups (n = 14): (1) methyl-methacrylate (MMA) monomer treatment for 3 min followed by AR insertion on the treated surfaces (positive control); (2) MMA monomer for 3 min followed by CR insertion on the treated surfaces (negative control); (3) A 2:1 mix of CR-AR treatment additional to a previous MMA monomer for 3 min followed by CR insertion on the treated surfaces; (4) A 2:1 mix of CR-AR and a bonding system treatments, respectively, additional to a previous MMA monomer for 3 min followed by CR insertion on the treated surfaces. A cylindrical split mold (5-mm diameter and 2.5-mm length) mounted over the treated surfaces was used to AR and CR materials insertion. After a 21-days period in artificial saliva storage, bond strength was assessed using a shear test device in a universal testing machine (EMIC, model DL 3000) at a crosshead speed of 0.5 mm/min until specimen failure. Data from bond strength assay were normally distributed (Kolmogorov–Smirnov, P = 0.05). One-way ANOVA and Dunnett’s test for multiple comparisons were applied to determine significant differences (P < 0.05). Failure mode was determined using a stereomicroscope (×40).