Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Ma... more Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Maria HYDROFLUORIC ACID AND IT IS EFFECT ON THE FLEXURAL STRENGTH OF A LITHIUM DISILICATEBASED GLASS CERAMIC AUTHOR: CATINA PROCHNOW ADVISER: LUIZ FELIPE VALANDRO Date and Place of Defense: Santa Maria – RS, 2015, July 08. This study aimed to evaluate the effect of different hydrfluoric acid (HF) concentrations on the flexural strength of a lithium disilicate based glass ceramic. Ceramic bar-specimens (14x4x1.2mm) were produced from ceramic blocks (e.max CAD, Ivoclar Vivadent), according to ISO 6872. The ceramic bars were randomly divided into 5 groups (n=23): SC (control) – without treatment, HF1, HF3, HF5 e HF10 – conditioned for 20 s with different acid concentrations: 1%, 3%, 5% e 10%, respectively. The etched ceramic surfaces were evaluated in a scanning electron microscope (SEM) and atomic force microscope (AFM). The roughness of treated surfaces was measured and the specimens were submitted to the 3-point flexural strength testing. Data were analyzed using 1-way ANOVA, Tukey‟s test (α=0.05), Pearson correlation and Weibull analyzis (modulus and characteristic strength). No statistical difference was found amoung groups for roughness and flexural strength, and the correlation between the data roughness and flexural strength was not statistically significance. The structural reliability (Weibull modulus) was similar among the tested groups, however, HF1 presented characteristic strength greater than HF10. The conditioning with different HF concentrations did not affect the surface roughness anfd flexural strength to a lithium disilicate based glass ceramic, when compared to untreated ceramic, regardless of the HF concentration used.
Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Ma... more Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Maria HYDROFLUORIC ACID AND IT IS EFFECT ON THE FLEXURAL STRENGTH OF A LITHIUM DISILICATEBASED GLASS CERAMIC AUTHOR: CATINA PROCHNOW ADVISER: LUIZ FELIPE VALANDRO Date and Place of Defense: Santa Maria – RS, 2015, July 08. This study aimed to evaluate the effect of different hydrfluoric acid (HF) concentrations on the flexural strength of a lithium disilicate based glass ceramic. Ceramic bar-specimens (14x4x1.2mm) were produced from ceramic blocks (e.max CAD, Ivoclar Vivadent), according to ISO 6872. The ceramic bars were randomly divided into 5 groups (n=23): SC (control) – without treatment, HF1, HF3, HF5 e HF10 – conditioned for 20 s with different acid concentrations: 1%, 3%, 5% e 10%, respectively. The etched ceramic surfaces were evaluated in a scanning electron microscope (SEM) and atomic force microscope (AFM). The roughness of treated surfaces was measured and the specimens were s...
The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are c... more The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are crucial to the clinical success of ceramic restorations. These factors are determined by bonding mechanisms guided by a specific surface treatment applied to promote micromechanical retention and chemical adhesion among the interfaces. Topographical changes of the cementation surface of ceramic restorations may be performed for bond improvements, consequently increasing the load-bearing ability under fatigue (fatigue resistance) of the restorations due to the interaction between the resin cement and the irregularities created by those surface modifications (e.g., acid etching, air abrasion). In this sense, it becomes important to elucidate some concepts related to the different glass–ceramic materials available on the dental market and clarify the correct surface treatment for each material to the clinicians, aiming for long-term success of ceramic restorations. In addition, glass–ceramics present different microstructures related to their chemical composition and arrangement, making it necessary to determine bonding procedures according to the glass–ceramic type. This chapter aims to clarify some concepts and characteristics regarding adhesion to glass–ceramic substrates to better guide dental clinicians.
The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are c... more The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are crucial to the clinical success of ceramic restorations. These factors are determined by bonding mechanisms guided by a specific surface treatment applied to promote micromechanical retention and chemical adhesion among the interfaces. Topographical changes of the cementation surface of ceramic restorations may be performed for bond improvements, consequently increasing the load-bearing ability under fatigue (fatigue resistance) of the restorations due to the interaction between the resin cement and the irregularities created by those surface modifications (e.g., acid etching, air abrasion). In this sense, it becomes important to elucidate some concepts related to the different glass–ceramic materials available on the dental market and clarify the correct surface treatment for each material to the clinicians, aiming for long-term success of ceramic restorations. In addition, glass–ceramic...
PURPOSE To evaluate the effect of different etching times of a self-etching ceramic primer on the... more PURPOSE To evaluate the effect of different etching times of a self-etching ceramic primer on the microshear bond strength (µSBS) and topographic surface pattern of a lithium-disilicate glass-ceramic. MATERIALS AND METHODS Ceramic slices were subjected to an in-lab simulation of CAD/CAM milling and randomly allocated to 10 groups (n = 35) considering two factors: "surface treatment" in 5 levels - one control group (5% hydrofluoric acid + silane application [HF5+SIL]), and 4 experimental groups using ceramic etching/primer (Monobond Etch & Prime, E&P) with different passive application times (40 s, 2 min, 5 min, or 10 min); and "aging" factor in 2 levels - short-term (after 24 h), or long-term (storage for 180 days + 12,000 thermal cycles). Composite cement cylinders were built and µSBS tests were run in a universal testing machine. The failure patterns were categorized, and complementary analyses with SEM and Atomic Force Microscopy (AFM) were performed. RESULTS ...
PURPOSE To evaluate the influence of new air-abrasion powders with different silica concentration... more PURPOSE To evaluate the influence of new air-abrasion powders with different silica concentrations (silica-coated aluminum oxide) and aging on the bond strength between composite cement and Y-TZP ceramic. MATERIALS AND METHODS Ceramic slices (7 x 6.3 x 2 mm3) were randomly allocated into 8 groups (n = 20) considering different surface treatments (SiC: silica-coated aluminum oxide particles; AlOx: aluminum oxide particles; 7% Si and 20% Si: experimental powders consisting of 7% and 20% silica-coated of AlOx respectively) and aging (baseline: 24 h at 37°C in water; aged: 90 days at 37°C in water + 12,000 thermal cycles). A blinded researcher performed the air-abrasion procedure for 10 s (identical parameters for all groups). Composite resin cylinders (Ø = 3 mm) were cemented onto the silanized ceramic surfaces, light cured, and subjected to shear bond-strength testing (wire loop Ø = 0.5 mm). The topography of the powders and air-abraded surfaces was analyzed using SEM and atomic force...
Journal of Esthetic and Restorative Dentistry, 2021
OBJECTIVE To evaluate the effect of surface treatments on optical, colorimetric, and surface char... more OBJECTIVE To evaluate the effect of surface treatments on optical, colorimetric, and surface characteristics of lithium disilicate glass-ceramic. MATERIALS AND METHODS Specimens (n = 5, IPS e.max CAD) were randomly allocated to the following treatments: mirror-polished: SiC papers; as-cut: mimicking CAD-CAM milling; ground: 90-120 μm-grit diamond bur; ground polished: ground, finished (46-30 μm-grit diamond bur), polished (diamond cups, brush and diamond paste); ground glazed: ground, glazed; ground polished glazed: association of methods. CIELAB color coordinates were obtained by a spectrophotometer. CIEDE2000 color differences (ΔE00 ) and the translucency parameter (TP00 ) were calculated. Light transmittance was assessed with a colorimeter. Surface characteristics (topography and roughness) were analyzed. Statistical differences for each condition and outcome were detected using one-way ANOVA with Tukey's post-hoc test (α = 0.05). RESULTS TP00 data show statistical reduction after grinding (p < 0.05), which was only restored with polishing (solely or with glazing). ΔE00 shows that grinding results in perceptible variations in color (above 0.81), which were restored after all post-processing protocols (exception to only glaze application in contact with a black background). Light transmittance data corroborated such performance. Polishing and glazing reduced roughness and improved surface topography. CONCLUSION Grinding statistically increased roughness, reduced translucency, light transmittance through the ceramic, and resulted on color differences. On contrary, polishing (followed or not by glazing) reduced roughness and enhanced ceramic translucency and light transmittance. Glaze also reduced roughness, but it still presented reduced translucency. The positioning (facing up or down) of the ceramic treated surface influenced the considered outcomes. CLINICAL SIGNIFICANCE Grinding with diamond burs results in a deleterious impact to the optical, colorimetric and surface characteristics of lithium disilicate ceramic. Thus, polishing (followed or not by glazing) is recommended for optical and topographical enhancements when lithium disilicate monolithic restorations require occlusal adjustments.
International Journal of Adhesion and Adhesives, 2021
Abstract The present study analyzed the fatigue performance of prefabricated fiber reinforced com... more Abstract The present study analyzed the fatigue performance of prefabricated fiber reinforced composite posts (FRC post) with different diameters by means of two different fatigue testing methods. A total of 69 FRC double-tapered posts, presenting 20mm in length associated with different coronal diameters (1.4, 1.6, 2.0 mm) were embedded with acrylic resin in PVC cylinders, maintaining 6 mm free from the coronal part of the post. The posts of each diameter were submitted to step stress testing (inclination: 45 degrees; initial load: 20 N; step-size: 10 N; cycles per step: 18,000; frequency: 5 Hz) (n= 5) or staircase testing (inclination: 45 degrees; initial load: 60% of the monotonic load-to-fracture reported on existing literature; increment: 10% of the monotonic load-to-fracture reported on existing literature; cycles: 18,000; frequency: 5 Hz) (n= 18). The statistical differences were determined for Kaplan-Meier and Mantel-Cox (Log-Rank) tests for step stress testing and based on confidence interval overlapping for staircase testing. All the failures were analyzed in a stereomicroscope (10× magnification) after the tests, and representative samples were analyzed by scanning electron microscope (500× and 1000× magnification). The FRC post with the wider diameter had greater fatigue failure load in step stress testing (DT1.4 – 56 N
Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Ma... more Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Maria HYDROFLUORIC ACID AND IT IS EFFECT ON THE FLEXURAL STRENGTH OF A LITHIUM DISILICATEBASED GLASS CERAMIC AUTHOR: CATINA PROCHNOW ADVISER: LUIZ FELIPE VALANDRO Date and Place of Defense: Santa Maria – RS, 2015, July 08. This study aimed to evaluate the effect of different hydrfluoric acid (HF) concentrations on the flexural strength of a lithium disilicate based glass ceramic. Ceramic bar-specimens (14x4x1.2mm) were produced from ceramic blocks (e.max CAD, Ivoclar Vivadent), according to ISO 6872. The ceramic bars were randomly divided into 5 groups (n=23): SC (control) – without treatment, HF1, HF3, HF5 e HF10 – conditioned for 20 s with different acid concentrations: 1%, 3%, 5% e 10%, respectively. The etched ceramic surfaces were evaluated in a scanning electron microscope (SEM) and atomic force microscope (AFM). The roughness of treated surfaces was measured and the specimens were submitted to the 3-point flexural strength testing. Data were analyzed using 1-way ANOVA, Tukey‟s test (α=0.05), Pearson correlation and Weibull analyzis (modulus and characteristic strength). No statistical difference was found amoung groups for roughness and flexural strength, and the correlation between the data roughness and flexural strength was not statistically significance. The structural reliability (Weibull modulus) was similar among the tested groups, however, HF1 presented characteristic strength greater than HF10. The conditioning with different HF concentrations did not affect the surface roughness anfd flexural strength to a lithium disilicate based glass ceramic, when compared to untreated ceramic, regardless of the HF concentration used.
Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Ma... more Master Course Dissertation Dental Sciences Post-Graduation Program Federal University of Santa Maria HYDROFLUORIC ACID AND IT IS EFFECT ON THE FLEXURAL STRENGTH OF A LITHIUM DISILICATEBASED GLASS CERAMIC AUTHOR: CATINA PROCHNOW ADVISER: LUIZ FELIPE VALANDRO Date and Place of Defense: Santa Maria – RS, 2015, July 08. This study aimed to evaluate the effect of different hydrfluoric acid (HF) concentrations on the flexural strength of a lithium disilicate based glass ceramic. Ceramic bar-specimens (14x4x1.2mm) were produced from ceramic blocks (e.max CAD, Ivoclar Vivadent), according to ISO 6872. The ceramic bars were randomly divided into 5 groups (n=23): SC (control) – without treatment, HF1, HF3, HF5 e HF10 – conditioned for 20 s with different acid concentrations: 1%, 3%, 5% e 10%, respectively. The etched ceramic surfaces were evaluated in a scanning electron microscope (SEM) and atomic force microscope (AFM). The roughness of treated surfaces was measured and the specimens were s...
The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are c... more The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are crucial to the clinical success of ceramic restorations. These factors are determined by bonding mechanisms guided by a specific surface treatment applied to promote micromechanical retention and chemical adhesion among the interfaces. Topographical changes of the cementation surface of ceramic restorations may be performed for bond improvements, consequently increasing the load-bearing ability under fatigue (fatigue resistance) of the restorations due to the interaction between the resin cement and the irregularities created by those surface modifications (e.g., acid etching, air abrasion). In this sense, it becomes important to elucidate some concepts related to the different glass–ceramic materials available on the dental market and clarify the correct surface treatment for each material to the clinicians, aiming for long-term success of ceramic restorations. In addition, glass–ceramics present different microstructures related to their chemical composition and arrangement, making it necessary to determine bonding procedures according to the glass–ceramic type. This chapter aims to clarify some concepts and characteristics regarding adhesion to glass–ceramic substrates to better guide dental clinicians.
The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are c... more The quality and durability of the adhesion among ceramic, resin cement, and tooth substrate are crucial to the clinical success of ceramic restorations. These factors are determined by bonding mechanisms guided by a specific surface treatment applied to promote micromechanical retention and chemical adhesion among the interfaces. Topographical changes of the cementation surface of ceramic restorations may be performed for bond improvements, consequently increasing the load-bearing ability under fatigue (fatigue resistance) of the restorations due to the interaction between the resin cement and the irregularities created by those surface modifications (e.g., acid etching, air abrasion). In this sense, it becomes important to elucidate some concepts related to the different glass–ceramic materials available on the dental market and clarify the correct surface treatment for each material to the clinicians, aiming for long-term success of ceramic restorations. In addition, glass–ceramic...
PURPOSE To evaluate the effect of different etching times of a self-etching ceramic primer on the... more PURPOSE To evaluate the effect of different etching times of a self-etching ceramic primer on the microshear bond strength (µSBS) and topographic surface pattern of a lithium-disilicate glass-ceramic. MATERIALS AND METHODS Ceramic slices were subjected to an in-lab simulation of CAD/CAM milling and randomly allocated to 10 groups (n = 35) considering two factors: "surface treatment" in 5 levels - one control group (5% hydrofluoric acid + silane application [HF5+SIL]), and 4 experimental groups using ceramic etching/primer (Monobond Etch & Prime, E&P) with different passive application times (40 s, 2 min, 5 min, or 10 min); and "aging" factor in 2 levels - short-term (after 24 h), or long-term (storage for 180 days + 12,000 thermal cycles). Composite cement cylinders were built and µSBS tests were run in a universal testing machine. The failure patterns were categorized, and complementary analyses with SEM and Atomic Force Microscopy (AFM) were performed. RESULTS ...
PURPOSE To evaluate the influence of new air-abrasion powders with different silica concentration... more PURPOSE To evaluate the influence of new air-abrasion powders with different silica concentrations (silica-coated aluminum oxide) and aging on the bond strength between composite cement and Y-TZP ceramic. MATERIALS AND METHODS Ceramic slices (7 x 6.3 x 2 mm3) were randomly allocated into 8 groups (n = 20) considering different surface treatments (SiC: silica-coated aluminum oxide particles; AlOx: aluminum oxide particles; 7% Si and 20% Si: experimental powders consisting of 7% and 20% silica-coated of AlOx respectively) and aging (baseline: 24 h at 37°C in water; aged: 90 days at 37°C in water + 12,000 thermal cycles). A blinded researcher performed the air-abrasion procedure for 10 s (identical parameters for all groups). Composite resin cylinders (Ø = 3 mm) were cemented onto the silanized ceramic surfaces, light cured, and subjected to shear bond-strength testing (wire loop Ø = 0.5 mm). The topography of the powders and air-abraded surfaces was analyzed using SEM and atomic force...
Journal of Esthetic and Restorative Dentistry, 2021
OBJECTIVE To evaluate the effect of surface treatments on optical, colorimetric, and surface char... more OBJECTIVE To evaluate the effect of surface treatments on optical, colorimetric, and surface characteristics of lithium disilicate glass-ceramic. MATERIALS AND METHODS Specimens (n = 5, IPS e.max CAD) were randomly allocated to the following treatments: mirror-polished: SiC papers; as-cut: mimicking CAD-CAM milling; ground: 90-120 μm-grit diamond bur; ground polished: ground, finished (46-30 μm-grit diamond bur), polished (diamond cups, brush and diamond paste); ground glazed: ground, glazed; ground polished glazed: association of methods. CIELAB color coordinates were obtained by a spectrophotometer. CIEDE2000 color differences (ΔE00 ) and the translucency parameter (TP00 ) were calculated. Light transmittance was assessed with a colorimeter. Surface characteristics (topography and roughness) were analyzed. Statistical differences for each condition and outcome were detected using one-way ANOVA with Tukey's post-hoc test (α = 0.05). RESULTS TP00 data show statistical reduction after grinding (p < 0.05), which was only restored with polishing (solely or with glazing). ΔE00 shows that grinding results in perceptible variations in color (above 0.81), which were restored after all post-processing protocols (exception to only glaze application in contact with a black background). Light transmittance data corroborated such performance. Polishing and glazing reduced roughness and improved surface topography. CONCLUSION Grinding statistically increased roughness, reduced translucency, light transmittance through the ceramic, and resulted on color differences. On contrary, polishing (followed or not by glazing) reduced roughness and enhanced ceramic translucency and light transmittance. Glaze also reduced roughness, but it still presented reduced translucency. The positioning (facing up or down) of the ceramic treated surface influenced the considered outcomes. CLINICAL SIGNIFICANCE Grinding with diamond burs results in a deleterious impact to the optical, colorimetric and surface characteristics of lithium disilicate ceramic. Thus, polishing (followed or not by glazing) is recommended for optical and topographical enhancements when lithium disilicate monolithic restorations require occlusal adjustments.
International Journal of Adhesion and Adhesives, 2021
Abstract The present study analyzed the fatigue performance of prefabricated fiber reinforced com... more Abstract The present study analyzed the fatigue performance of prefabricated fiber reinforced composite posts (FRC post) with different diameters by means of two different fatigue testing methods. A total of 69 FRC double-tapered posts, presenting 20mm in length associated with different coronal diameters (1.4, 1.6, 2.0 mm) were embedded with acrylic resin in PVC cylinders, maintaining 6 mm free from the coronal part of the post. The posts of each diameter were submitted to step stress testing (inclination: 45 degrees; initial load: 20 N; step-size: 10 N; cycles per step: 18,000; frequency: 5 Hz) (n= 5) or staircase testing (inclination: 45 degrees; initial load: 60% of the monotonic load-to-fracture reported on existing literature; increment: 10% of the monotonic load-to-fracture reported on existing literature; cycles: 18,000; frequency: 5 Hz) (n= 18). The statistical differences were determined for Kaplan-Meier and Mantel-Cox (Log-Rank) tests for step stress testing and based on confidence interval overlapping for staircase testing. All the failures were analyzed in a stereomicroscope (10× magnification) after the tests, and representative samples were analyzed by scanning electron microscope (500× and 1000× magnification). The FRC post with the wider diameter had greater fatigue failure load in step stress testing (DT1.4 – 56 N
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