RESUMEN
This study aimed to evaluate the effect of etching time and hydrofluoric acid (HF) concentration on the fatigue failure load and surface characteristics of zirconia-reinforced lithium silicate glass (ZLS) ceramic cemented to a dentin-like, fiber reinforced epoxy resin. Ceramic (Suprinity, VITA) (1.0mm thick) and epoxy resin (2.5mm thick) discs (10mm diameter) were produced. The bonding surface of the ceramic samples was nonetched (control group), or etched for 30, 60 or 90s by 5% or 10% HF. The epoxy resin discs were etched by 10% HF for 30s followed by the application of an adhesive material (Single Bond Universal, 3M ESPE). Pairs of ceramic/epoxy resin discs were cemented with a dual cure resin cement. The fatigue failure load was determined by the staircase method (500,000 cycles at 20Hz; initial load = 925N; step size = 45N). In 10% HF the etching time was shown to influence the fatigue failure load, which increased as the etching time increased (30s < 60s < 90s), and in 5% HF the fatigue failure load was not shown to be affected by the etching time; the lowest fatigue failure loads were produced in the control group without ceramic etching followed by 10% HF acid etching for 30s. Topography analysis showed variations based on the etching protocols. All fractures (radial cracks) were shown to originate from defects at the ceramic surface on the cementing interface. For fatigue loading improvements of ZLS ceramic, 10% HF acid etching for 90s and silanization of the ceramic surface is recommended.
Asunto(s)
Cerámica/química , Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Porcelana Dental/química , Ácido Fluorhídrico/química , Litio/química , Circonio/química , Bisfenol A Glicidil Metacrilato/química , Resinas Compuestas/química , Grabado Dental/instrumentación , Análisis del Estrés Dental , Ensayo de Materiales , Resistencia al Corte , Silicatos , Propiedades de SuperficieRESUMEN
PURPOSE: To assess the effect of the erbium:yttrium aluminum garnet (Er:YAG) laser on bond strength of a total-etch adhesive system to the caries-affected dentin on the gingival wall. MATERIALS AND METHODS: Ten human molars with proximal carious lesions were randomly divided into two groups. In the first group, the carious dentin was removed with a bur, whereas in the second group it was removed with the Er:YAG laser. Carious lesions were excavated with one of these two techniques until laser fluorescence values decreased to 15 in the center of the lesions. The teeth were then restored with a total-etch adhesive system (Adper Single Bond 2) and composite resin (Filtek Z250). Five teeth from each group were sectioned to obtain 1 mm2 stick-shaped microtensile specimens from each tooth. Twenty-five specimens were obtained for each group with using this technique. The data were analyzed in independent-samples t-test (α = 0.05). For each removal technique, one sample was analyzed using scanning electron microscopy. RESULTS: No statistically significant differences were found between the bond strength of the Er:YAG laser and the bur-treated groups (P > 0.05). CONCLUSION: The Er:YAG laser treatment did not negatively affect the bonding performance of the total-etch adhesive system to caries-affected dentin on the gingival wall.
Asunto(s)
Resinas Compuestas/química , Preparación de la Cavidad Dental/métodos , Cementos Dentales/química , Grabado Dental/métodos , Láseres de Estado Sólido/uso terapéutico , Resinas Compuestas/uso terapéutico , Caries Dental/terapia , Preparación de la Cavidad Dental/instrumentación , Cementos Dentales/uso terapéutico , Grabado Dental/instrumentación , Restauración Dental Permanente , Dentina/química , Dentina/ultraestructura , Humanos , Microscopía Electrónica de Rastreo , Diente Molar , Distribución Aleatoria , Resistencia a la TracciónRESUMEN
AIM: The objective of the present study was to determine which of six bonding protocols yielded a clinically acceptable shear bond strength (SBS) of metal orthodontic brackets to CAD/CAM lithium disilicate porcelain restorations. A secondary aim was to determine which bonding protocol produced the least surface damage at debond. METHODS: Sixty lithium disilicate samples were fabricated to replicate the facial surface of a mandibular first molar using a CEREC CAD/CAM machine. The samples were split into six test groups, each of which received different mechanical/chemical pretreatment protocols to roughen the porcelain surface prior to bonding a molar orthodontic attachment. Shear bond strength testing was conducted using an Instron machine. The mean, maximum, minimal, and standard deviation SBS values for each sample group including an enamel control were calculated. A t-test was used to evaluate the statistical significance between the groups. RESULTS: No significant differences were found in SBS values, with the exception of surface roughening with a green stone prior to HFA and silane treatment. This protocol yielded slightly higher bond strength which was statistically significant. CONCLUSION: Chemical treatment alone with HFA/silane yielded SBS values within an acceptable clinical range to withstand forces applied by orthodontic treatment and potentially eliminates the need to mechanically roughen the ceramic surface.
Asunto(s)
Recubrimiento Dental Adhesivo/métodos , Porcelana Dental/química , Restauración Dental Permanente/métodos , Soportes Ortodóncicos , Grabado Ácido Dental/métodos , Óxido de Aluminio/química , Diseño Asistido por Computadora , Aleaciones Dentales/química , Desconsolidación Dental/métodos , Esmalte Dental/anatomía & histología , Grabado Dental/instrumentación , Grabado Dental/métodos , Análisis del Estrés Dental/instrumentación , Diamante/química , Humanos , Ácido Fluorhídrico/química , Ensayo de Materiales , Resistencia al Corte , Silanos/química , Dióxido de Silicio/química , Estrés Mecánico , Propiedades de SuperficieRESUMEN
Aim. This study sought to compare the microleakage of three adhesive systems in the context of Erbium-YAG laser and diamond bur cavity procedures. Cavities were restored with composite resin. Materials and Methods. Standardized Class V cavities were performed in 72 extracted human teeth by means of diamond burs or Er-YAG laser. The samples were randomly divided into six groups of 12, testing three adhesive systems (Clearfil s(3) Bond Plus, Xeno® Select, and Futurabond U) for each method used. Cavities were restored with composite resin before thermocycling (methylene blue 2%, 24 h). The slices were prepared using a microtome. Optical microscope photography was employed to measure the penetration. Results. No statistically significant differences in microleakage were found in the use of bur or laser, nor between adhesive systems. Only statistically significant values were observed comparing enamel with cervical walls (p < 0.001). Conclusion. It can be concluded that the Er:YAG laser is as efficient as diamond bur concerning microleakage values in adhesive restoration procedures, thus constituting an alternative tool for tooth preparation.
Asunto(s)
Preparación de la Cavidad Dental , Cementos Dentales/farmacología , Grabado Dental , Láseres de Estado Sólido , Preparación de la Cavidad Dental/instrumentación , Preparación de la Cavidad Dental/métodos , Grabado Dental/instrumentación , Grabado Dental/métodos , Femenino , Humanos , MasculinoRESUMEN
BACKGROUND/OBJECTIVES: This study investigated the biomechanical properties and bone-implant intersurface response of machined and laser surface-treated stainless steel (SS) mini-screw implants (MSIs). MATERIAL AND METHODS: Forty-eight 1.3mm in diameter and 6mm long SS MSIs were divided into two groups. The control (machined surface) group received no surface treatment; the laser-treated group received Nd-YAG laser surface treatment. Half in each group was used for examining surface roughness (Sa and Sq), surface texture, and facture resistance. The remaining MSIs were placed in the maxilla of six skeletally mature male beagle dogs in a randomized split-mouth design. A pair with the same surface treatment was placed on the same side and immediately loaded with 200 g nickel-titanium coil springs for 8 weeks. After killing, the bone-implant contact (BIC) for each MSI was calculated using micro computed tomography. Analysis of variance model and two-sample t test were used for statistical analysis with a significance level of P <0.05. RESULTS: The mean values of Sa and Sq were significantly higher in the laser-treated group compared with the machined group (P <0.05). There were no significant differences in fracture resistance and BIC between the two groups. LIMITATION: animal study CONCLUSIONS/IMPLICATIONS: Laser treatment increased surface roughness without compromising fracture resistance. Despite increasing surface roughness, laser treatment did not improve BIC. Overall, it appears that medical grade SS has the potential to be substituted for titanium alloy MSIs.
Asunto(s)
Tornillos Óseos , Interfase Hueso-Implante/anatomía & histología , Aleaciones Dentales/efectos de la radiación , Grabado Dental/métodos , Láseres de Estado Sólido , Métodos de Anclaje en Ortodoncia/instrumentación , Acero Inoxidable/efectos de la radiación , Animales , Interfase Hueso-Implante/diagnóstico por imagen , Aleaciones Dentales/química , Grabado Dental/instrumentación , Perros , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional/métodos , Masculino , Maxilar/cirugía , Níquel/química , Alambres para Ortodoncia , Distribución Aleatoria , Acero Inoxidable/química , Estrés Mecánico , Propiedades de Superficie , Titanio/química , Torque , Microtomografía por Rayos XAsunto(s)
Aleaciones Dentales/química , Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Cementos de Resina/química , Abrasión Dental por Aire/instrumentación , Óxido de Aluminio/química , Cementación/métodos , Aleaciones de Cromo/química , Grabado Dental/instrumentación , Materiales Dentales/química , Aleaciones de Oro/química , Humanos , Curación por Luz de Adhesivos Dentales , Silanos/química , Dióxido de Silicio/química , Propiedades de Superficie , Titanio/químicaRESUMEN
INTRODUCTION: The purposes of this study were to characterize enamel surfaces treated with sandblasting, acid etching, or sandblasting followed by acid etching for bonding of orthodontic adhesives and to evaluate the enamel-adhesive interfaces. METHODS: Buccal premolar surfaces were sandblasted, acid etched, sandblasted and subsequently acid etched, or left intact. For 2 treatments (acid etching and sandblasting plus acid etching), orthodontic brackets were bonded for resin infiltration assessment. Surface roughness and enamel loss were evaluated by optical profilometry, and surface morphology and elemental composition were examined by low-vacuum scanning electron microscope/energy dispersive x-ray analysis, whereas interfacial resin infiltration was assessed by high-vacuum scanning electron microscopy. Differences were statistically analyzed by 1-way analysis of variance and Tukey-Kramer multiple comparison tests or t tests (α = 0.05). RESULTS: The sandblasted and sandblasted-plus-acid-etched groups showed higher surface roughness values than the acid-etched group. Sandblasting plus acid etching removed more enamel than did sandblasting or acid etching alone. Sandblasting plus acid etching demonstrated a more uniform type I etching pattern, without alumina particles implanted in the enamel, unlike sandblasting. No difference was found in the extent of resin infiltration between the bonded acid-etched and sandblasted-plus-acid-etched groups, although the latter showed improved infiltration characteristics. CONCLUSIONS: Sandblasting-plus-acid-etching treatment creates a rough enamel surface, typical of type I etching, with the greatest extent of enamel loss, free of alumina interferences, demonstrating the same extent of resin infiltration as acid etching, but exhibiting improved infiltration quality.
Asunto(s)
Grabado Ácido Dental/métodos , Óxido de Aluminio/química , Recubrimiento Dental Adhesivo , Esmalte Dental/ultraestructura , Grabado Dental/métodos , Soportes Ortodóncicos , Cementos de Resina/química , Calcio/análisis , Resinas Compuestas/química , Grabado Dental/instrumentación , Microanálisis por Sonda Electrónica , Humanos , Imagenología Tridimensional/métodos , Curación por Luz de Adhesivos Dentales , Microscopía Electrónica de Rastreo , Oxígeno/análisis , Ácidos Fosfóricos/química , Fósforo/análisis , Propiedades de SuperficieRESUMEN
AIM: The aim of this study was to evaluate the influence of the subject's age and dentin etching time on the clinical performance of a two-step etch-and-rinse adhesive in class V non-carious cervical lesions (NCCLs). MATERIALS AND METHODS: Forty patients with NCCLs (classified as degrees 2 and 3 of dentin sclerosis) were enrolled in this study. The lesions were selected and assigned into two groups (n = 70/group) according to the subject's age: (G1) between 21-35 years old and (G2) between 40-54 years old. Each group was randomly divided into two subgroups (n = 35/group) according to dentin etching time using recommended application time (15 s) and an extended application time (30 s). A total of 140 restorations with XP Bond (Dentsply DeTrey, Germany) were placed. The composite resin Esthet X (Dentsply) was placed incrementally. All restorations were evaluated using the modified USPHS criteria. Data was analyzed by the McNemar and chi-square tests (p < 0.05). RESULTS: At the end of 2 years, 132 restorations (94.2% recall rate) were evaluated. The 24-month retention rates (%) were 93.5 for G1(15), 97.1 for G1(30), 93.9 for G2(15), and 97.0 for G2(30). There were no statistical differences in the retention rates in each recall period among groups. CONCLUSION: For the selected age groups, neither the subject's age nor the etching time had any influence on the clinical performance of XP Bond adhesive in NCCLs over a 24-month period. CLINICAL RELEVANCE: The clinical effectiveness of the XP Bond was excellent after 2 years of clinical service. Long-term clinical evaluations are necessary to confirm this finding.
Asunto(s)
Cementos Dentales/farmacología , Grabado Dental/métodos , Adulto , Factores de Edad , Grabado Dental/instrumentación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de TiempoRESUMEN
OBJECTIVES: The aim of the study was to determine the effect of CO2 laser on surface roughness of In-Ceram-Alumina-ceramic. MATERIALS AND METHODS: Four aluminum-oxide ceramic disc specimens were prepared of In-Ceram Alumina. Discs received CO2 laser irradiation with different engraving speeds (100, 400, 600 and 800 mm/min) as a surface treatment. The roughness of the surfaces was measured on digital elevation models reconstructed from stereoscopic images acquired by scanning-electron-microscope. Surface roughness data were analyzed with One-Way-Analysis-of-Variance at a significance level of p<0.05. RESULTS: There was no significant difference between the roughness values (p=0.82). Due to higher laser durations, partial melting signs were observed on the surfaces. Tearing, smearing and swelling occurred on melted surfaces. Swelling accompanying melting increased the surface roughness, while laser power was fixed and different laser engraving speeds were applied. CONCLUSION: Although different laser irradiation speeds did not affect the roughness of ceramic surfaces, swelling was observed which led to changes on surfaces.
Asunto(s)
Grabado Dental/instrumentación , Porcelana Dental/efectos de la radiación , Láseres de Gas , Óxido de Aluminio/química , Óxido de Aluminio/efectos de la radiación , Cerámica/química , Cerámica/efectos de la radiación , Porcelana Dental/química , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Proyectos Piloto , Dosis de Radiación , Propiedades de Superficie , Factores de TiempoRESUMEN
AIM: The purpose of this study was to evaluate the effect of sandblasting, carbon dioxide (CO2), and erbium,chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers on the microshear bond strength of zirconia to resin cement. METHODS: Sixty-one sintered yttria stabilized tetragonal zirconia blocks (10 × 5 × 2 mm) were prepared and divided into four experimental groups (n = 15); one sample was retained as a control. The samples were treated by aluminium oxide air abrasion, CO24W, Er,Cr:YSGG 3W, and Er,Cr:YSGG 2W, respectively. One sample from each group and the control sample were analyzed by scanning electron microscope. Panavia F2.0 resin microcylinders were prepared and placed on treated surfaces, light cured, and incubated for 48 h. Microshear bond strength testing was done by a microtensile tester machine, and the type of bond failures were determined by stereomicroscope. Data were analyzed by one-way anova and Tukey's test at a significance level of P < 0.05. RESULTS: Air abrasion showed the highest microshear bond strength (P < 0.05) among all groups. CO2and Er,Cr:YSGG 3W laser showed significantly higher bond strength than Er,Cr:YSGG 2W (P < 0.05). Apparent micromechanical roughening and irregularities were seen in the air abrasion-treated samples, and the bond failure was mostly mixed type. In the laser-treated surfaces, the roughness was much less than the air abrasion-treated surfaces, and the mode of failure was almost pure adhesive. CONCLUSION: Air abrasion has a greater effect than CO2and Er,Cr:YSGG lasers in the treatment of zirconia ceramic surfaces to enhance the bonding strength of resin cement to zirconia. CO2laser at 4W and Er,Cr:YSGG laser at only 3-W output power can be regarded as surface treatment options for roughening the zirconia surface to establish better bond strength with resin cements.
Asunto(s)
Cerámica/química , Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Materiales Dentales/química , Rayos Láser , Cementos de Resina/química , Itrio/química , Circonio/química , Adhesividad , Óxido de Aluminio/química , Grabado Dental/instrumentación , Análisis del Estrés Dental/instrumentación , Humanos , Humedad , Láseres de Gas , Láseres de Estado Sólido , Curación por Luz de Adhesivos Dentales/métodos , Ensayo de Materiales , Microscopía Electrónica de Rastreo/métodos , Resistencia al Corte , Estrés Mecánico , Propiedades de Superficie , Temperatura , Factores de TiempoRESUMEN
This study was designed to evaluate laser-sintered early-loaded 1-piece implants (OPI) based on clinical and radiographic findings. Thirty OPI were placed in the mandibular premolar area and subjected to early loading after 3 weeks of initial placement; patients were followed up for 6 months. Clinical evaluation included pocket depth, gingival health, implant stability, and esthetics. Periapical radiographs were used to measure the marginal bone loss (MBL). All implants were considered successful resulting in a survival rate of 100%. A remarkable difference (P < 0.01) existed when comparing MBL levels at 1 month with those at 3 and 6 months. Significant differences (P < 0.01) existed when comparing implant stability at 1 month to 3 months and at 3 months to 6 months. Moreover, significant differences (P < 0.01) were observed when comparing peri-implant probing depth at 1 month to that at 3 and 6 months on both the mesial and distal sides. The mean value of pink esthetic score was 11 at time of final restoration. The laser-treated early-loaded OPI design is associated with satisfactory clinical and radiographic follow-up results and it is a good alternative to the 2-piece design.
Asunto(s)
Diente Premolar , Grabado Dental/métodos , Implantes Dentales de Diente Único , Diseño de Prótesis Dental , Carga Inmediata del Implante Dental , Rayos Láser , Mandíbula/cirugía , Pérdida de Hueso Alveolar/diagnóstico por imagen , Grabado Dental/instrumentación , Implantación Dental Endoósea/métodos , Estética Dental , Estudios de Seguimiento , Humanos , Oseointegración/fisiología , Índice Periodontal , Bolsa Periodontal/clasificación , Radiografía de Mordida Lateral , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
STATEMENT OF PROBLEM: Different techniques have been suggested for cleaning dentin surfaces after the removal of an interim prosthesis and before the application of a bonding agent. How different surface-cleaning techniques affect the bond strength of the composite resin restorations is not clear. PURPOSE: The purpose of this study was to investigate the effects of different surface-cleaning techniques on the bond strength of composite resin restorations and the surface topography of the prepared tooth surfaces. MATERIAL AND METHODS: The occlusal surfaces of 25 molars were ground until the dentin was exposed. A bonding agent and interim cement were applied on the teeth. The teeth were divided into 5 groups (n=5) according to the method used for surface-cleaning (microairborne-particle abrasion, alcohol, rubber-rotary instrument, desiccating agent, and control). Once the surfaces of the teeth had been cleaned, the same bonding material was applied to the teeth. A 5-mm-thick composite resin layer was built up. Each specimen was sectioned to microbars, and 6 centrally located beams were selected for microtensile testing (n=30) (1.10 ±0.10 mm). The data were statistically analyzed with 1-way ANOVA (1-sample Kolmogorov-Smirnov test). The Bonferroni test was used for significantly different groups (α=.05). One specimen from each group was observed under a scanning electron microscope and an atomic force microscope. Energy dispersive x-ray analysis also was performed. RESULTS: Bond strength values were in the following descending order: microairborne-particle abrasion, desiccating agent, alcohol, rubber-rotary instrument, control. Differences between the microairborne-particle abrasion group and the remainder of the groups, desiccating agent--rubber-rotary instrument, desiccating agent-control, alcohol--rubber-rotary instrument, and alcohol-control groups, were statistically significant (P<.05). The microairborne-particle abrasion group displayed the roughest surface and a different surface topography from the remainder of the groups. Increased aluminum was observed in the microairborne-particle abrasion group. CONCLUSIONS: Surface-cleaning techniques, except for the rubber-rotary instrument, increased the bond strength of composite resin. The roughest dentin surfaces and highest bond strength were achieved with the microairborne-particle abrasion technique.
Asunto(s)
Abrasión Dental por Aire/métodos , Resinas Compuestas/química , Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Materiales Dentales/química , Restauración Dental Permanente/métodos , Adulto , Abrasión Dental por Aire/instrumentación , Cementos Dentales/química , Grabado Dental/instrumentación , Dentina/ultraestructura , Etanol/química , Humanos , Higroscópicos/química , Ensayo de Materiales , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Diente Molar/ultraestructura , Cementos de Resina/química , Goma/química , Auto-Curación de Resinas Dentales , Espectrometría por Rayos X , Estrés Mecánico , Propiedades de Superficie , Resistencia a la Tracción , Adulto Joven , Óxido de Zinc/químicaAsunto(s)
Recubrimiento Dental Adhesivo/métodos , Materiales Dentales/química , Prótesis Dental , Cementos de Resina/química , Circonio/química , Óxido de Aluminio/química , Resinas Compuestas/química , Grabado Dental/instrumentación , Grabado Dental/métodos , Humanos , Metacrilatos/química , Silanos/química , Propiedades de SuperficieRESUMEN
BACKGROUND: The aim of this research is to evaluate cyclic (CSBS) and static shear bond strengths (SSBS) of metal orthodontic brackets bonded to composite laminates using different conditioning protocols. METHODS: A total of 80 direct nanofilled composite laminate veneers were prepared on permanent incisors and divided into four equal groups according to different surface treatments. In group 1, diamond bur was used. In group 2, microetcher (50-µm alumina particles) was utilized. In group 3, 38% phosphoric acid treatment for 60 s was done. In group 4 (control group), metal brackets were bonded to the untreated veneer surfaces using no-mix adhesive resin. SSBS testing was carried out for ten specimens, while CSBS testing was done for another ten specimens from each group. The data were subjected to analysis of variance and Scheffe post hoc test. The chi-square test was used to determine significant differences in the adhesive remnant index scores among different groups. RESULTS: Statistically significant difference was only found between SSBS of brackets bonded when surface treatment was done using the diamond bur, microetcher, and the phosphoric acid at P<0.05. With regard to CSBS, the use of bur treatment and microetching achieved the highest values; however, there was no significant difference between these two groups. With phosphoric acid, surface treatment achieved the lowest CSBS value; there was no significant difference between this group and the control group. The SSBS was significantly higher than CSBS in all groups. CONCLUSIONS: Roughening composite laminate veneers with either diamond bur or microetcher could be used successfully as an alternative to provide higher bond strength than phosphoric acid surface treatment. Cyclic loading significantly decreased bond strength.
Asunto(s)
Resinas Compuestas/química , Aleaciones Dentales/química , Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Materiales Dentales/química , Coronas con Frente Estético , Soportes Ortodóncicos , Grabado Ácido Dental/métodos , Adhesividad , Óxido de Aluminio/química , Luces de Curación Dental , Grabado Dental/instrumentación , Análisis del Estrés Dental/instrumentación , Diamante/química , Humanos , Ensayo de Materiales , Nanocompuestos/química , Ácidos Fosfóricos/química , Polimerizacion , Resistencia al Corte , Acero Inoxidable/química , Estrés Mecánico , Propiedades de SuperficieRESUMEN
PURPOSE: To evaluate the effect of nozzle distance, nozzle angle, and deposition duration on the silica content attained on zirconia by air abrasion. MATERIALS AND METHODS: Disk-shaped zirconia (LAVA, 3M ESPE) (diameter: 10 mm, thickness: 2 mm) specimens (N = 54) were obtained. They were wet-ground finished using 600-, 800-, and 1200-grit silicone carbide abrasive papers in sequence and ultrasonically cleaned. The specimens were mounted in a specially designed apparatus that allowed the chairside air-abrasion device to be operated under standard conditions. Alumina-coated silica particles (CoJet Sand, 3M ESPE) were deposited on the zirconia disk surfaces varying the following parameters: a) nozzle distance (2, 5, 10 mm), and b) deposition duration (5, 13, 20 s) at two nozzle angles (45 and 90 degrees) under 2.5 bar pressure at three locations on each ceramic disk. The specimen surfaces were then gently air dried for 20 s. Silica content in weight percentage (wt%) was measured from 3 surfaces on each disk using Energy Dispersive X-ray Spectroscopy (EDS) (150X) in an area of 0.8 mm x 0.6 mm (n = 3 per group). Surface topographies were evaluated using SEM. Data were analyzed using ANOVA and Tukey's tests (α = 0.05). RESULTS: Nozzle angle (p = 0.003) and deposition duration (p = 0.03) significantly affected the results, but nozzle distance (p = 0.569) did not. A significantly higher amount of silica (wt%) was achieved when the nozzle angle was 45 degrees to the surface in all distance-duration combinations (16.7 to 28.2 wt%) compared to the 90-degree nozzle angle (10.7 to 18.6 wt%) (p < 0.001). The silica amount was significantly higher after 20-s deposition duration than after 13 s (p < 0.05). EDS analysis demonstrated not only Si but also Al, Zr, and O traces on the substrate. SEM images indicated that deposition at a nozzle distance of 2 mm often created cavitations in zirconia. CONCLUSION: Effective silica deposition using a charside air-abrasion device can be achieved when the nozzle is held at 45 degrees to the surface with more than 2-mm nozzle distance for 20 s.
Asunto(s)
Grabado Dental/instrumentación , Materiales Dentales/química , Dióxido de Silicio/química , Circonio/química , Aluminio/análisis , Óxido de Aluminio/química , Compuestos Inorgánicos de Carbono/química , Grabado Dental/métodos , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oxígeno/análisis , Presión , Silicio/análisis , Compuestos de Silicona/química , Espectrometría por Rayos X , Propiedades de Superficie , Factores de Tiempo , Circonio/análisisRESUMEN
OBJECTIVES: To evaluate the effects of surface treatment, surface hydration (SH) and application method (AM) on the tensile bond strength of the Silorane Adhesive System (SAS) to dentine. METHODS: Ninety bovine teeth were used. For the control group (n=10), each dentine surface was treated according to the manufacturer's instructions of the SAS. The remaining teeth were randomly distributed into two groups (n=40), according to the type of dentine surface treatment (ST)-37% phosphoric acid or Er:YAG Laser prior to the application of the SAS. Each group was further divided into 2 subgroups (n=20), according to the SH status: dry (D) or wet (W). Each subgroup was further divided into 2 subgroups (n=10), according to the application method [AM: Active (AC) mode or Passive (PA) mode]. A coat of resin composite (Filtek P90) was applied on the surface. Artificial ageing was performed with a thermo-mechanical cycling machine. The specimens were sectioned into 1mm×1mm×10mm sticks and stressed to failure using a universal testing machine. The remaining teeth in each group were used for Scanning Electron Microscopy to examine the fractured area. Data were subjected to a three-way ANOVA, Tukey's test and Dunnet's test (α=0.05). RESULTS: The ANOVA showed significant differences for SH and AM, but not for ST. For SH, the results of Tukey's test were (in MPa): D - 14.9(±3.8)(a), W - 17.1(±4.3)(b); and for AM: PA - 14. 9(±4.2)(a), AC - 17.1(±3.9)(b). CONCLUSIONS: Acid etching, when combined with a moist dentine surface and the use of primer agitation, improves the bond strength of the SAS to dentine. CLINICAL SIGNIFICANCE: According to the results of the present in vitro study, modification of the application protocols for the silorane-based adhesive system may improve its clinical performance.
Asunto(s)
Recubrimiento Dental Adhesivo/métodos , Grabado Dental/métodos , Recubrimientos Dentinarios/química , Dentina , Resinas de Silorano , Animales , Bovinos , Resinas Compuestas , Grabado Dental/instrumentación , Análisis del Estrés Dental , Láseres de Estado Sólido , Microscopía Electrónica de Rastreo , Ácidos Fosfóricos , Distribución Aleatoria , Resistencia a la Tracción , Vibración , Humectabilidad , Agentes MojantesRESUMEN
BACKGROUND: The purpose of this study was to evaluate the bond strengths between dentine and resin composite obtained after Er:YAG laser treatment of crown or root dentine used together with self-etch and total-etch adhesive systems. METHODS: One etch-and-rinse adhesive (Single Bond, 3M, USA) and one self-etch system (Clearfil SE Bond, Kuraray, Japan) were applied to root and crown dentine prepared with a regular bur in a turbine or with an Er:YAG laser. The shear bond strength was determined after thermocycling and statistically analysed using independent t-tests. RESULTS: Crown sites bonded using Clearfil SE Bond and Single Bond adhesives yielded bond strengths similar to that of root dentine sites (p > 0.05). Clearfil SE Bond was stronger in both the lased and non-lased groups (p < 0.05). The lowest bond strength was obtained when Single Bond without acid etching was used on Er:YAG ablated dentine. When total-etch adhesive was used, there were significant differences (p < 0.05) between the laser-ablated and laser-ablated/acid-etched and bur-cut/acid-etched groups. CONCLUSIONS: Er:YAG laser irradiation of root and crown dentine conducted prior to the adhesive protocol adversely affected adhesion and decreased bond strength compared with traditional preparation.
Asunto(s)
Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Recubrimientos Dentinarios , Dentina , Cementos de Resina , Bisfenol A Glicidil Metacrilato , Grabado Dental/instrumentación , Análisis del Estrés Dental , Humanos , Láseres de Estado Sólido , Resistencia al Corte , Corona del Diente , Raíz del DienteRESUMEN
Dental restorations made of zirconia are usually selectively adjusted chairside to eliminate occlusal or internal interferences that can impair the mechanical properties of ceramic framework material. Effects of polishing procedures on zirconia after chipping or simply glazing the monolithic zirconia restorations are not known. This study evaluated the effects of different surface treatment procedures--namely, glazing or grinding, finishing, and polishing regimens--on the flexural strength and fracture toughness of a zirconia core material. Forty zirconia specimens were prepared and divided into two main groups (n = 20) according to the type of surface treatment (glazed or ground, finished, and polished). Each group was further divided into two subgroups (n = 10) according to type of mechanical test (flexural strength and fracture toughness). The roughness measurements were performed before mechanical testing. Qualitative evaluation of representative specimens of each subgroup was performed using SEM. The surface roughness mean (µm; ± standard deviations) recorded for the glazed specimens (0.94 ± 0.2) was significantly lower than that of the finished and polished group (3.01 ± 0.1) (P < 0.05). The glazed zirconia showed significantly higher flexural strength (385.4 ± 45.4 MPa) and fracture toughness (6.07 ± 1 MPa.m½) values than the ground, finished, polished zirconia (302.4 ± 47.6 MPa and 2.14 ± 0.5 MPa.m½) (P = 0.002 and P < 0.001 for flexural strength and fracture toughness, respectively). A smooth topographic pattern after glazing could not be obtained after finishing and polishing. Grinding, finishing, and polishing markedly decreased the flexural strength and fracture toughness of zirconia compared to the glazed groups.
Asunto(s)
Materiales Dentales/química , Pulido Dental/métodos , Porcelana Dental/química , Circonio/química , Fuerza Compresiva , Grabado Dental/instrumentación , Grabado Dental/métodos , Pulido Dental/instrumentación , Análisis del Estrés Dental/instrumentación , Diamante/química , Calor , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Docilidad , Elastómeros de Silicona/química , Estrés Mecánico , Propiedades de SuperficieRESUMEN
OBJECTIVE: To compare four different surface treatment methods and determine which produces adequate bond strength between ceramic brackets and facets of porcelain (feldspathic), and evaluate the Adhesive Remnant Index (ARI) scores. MATERIALS AND METHODS: Ten facets of porcelain specimens with glazed surfaces were used for each group. The specimens were randomly assigned to one of the following treatment conditions of the porcelain surface: (1) no surface treatment (control group), (2) fine diamond bur + orthophosphoric acid gel 37%, (3) hydrofluoric acid (HFL) 10%, and (4) HFL 10% + silane. Ceramic brackets were bonded with the adhesive cement Transbond XT. The shear bond strength values were measured on a universal testing machine at a crosshead speed of 0.5 mm/min. RESULTS: There was a significant difference (P<0.05) between the control group and all other groups. There was no significant difference (P<0.05) between treated porcelain surface with diamond bur + orthophosphoric acid gel 37% (4.8 MPa) and HFL 10% (6.1 MPa), but the group treated with HFL 10% had clinically acceptable bond strength values. The group treated with HFL 10% + silane (17.5 MPa) resulted in a statistically significant higher tensile bond strength (P<0.05). In group 4, 20% of the porcelain facets displayed damage. CONCLUSION: Etching of the surface with HFL increased the bond strength values. Silane application was recommended to bond a ceramic bracket to the porcelain surface in order to achieve bond strengths that are clinically acceptable.