RESUMEN
PURPOSE: This study evaluated the adherence of dental porcelain to a milled, noncast titanium (Ti) surface with a gold sputter coating to evaluate a possible new practical surface treatment for enhancing the bond strength between Ti and porcelain. MATERIALS AND METHODS: Milled, noncast Ti strips were created by computer-aided design and manufacturing processes. The milled, noncast Ti strips were sandblasted with alumina particles and were then sequentially subjected to gold sputter coating treatments of 150- and 300-second duration. Low-fusion dental porcelain was then sintered onto the surface-treated Ti strips. The bond strengths of the Ti/porcelain specimens were evaluated using a three-point bending test (ISO 9693). Surface characterizations of the specimens were carried out with X-ray photoelectron spectrometry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. RESULTS: The results indicated that the bond strengths of all the Ti/porcelain groups were greater than the minimum requirement (25 MPa) as prescribed by ISO 9693. The gold sputter coating increased the oxidation resistance (or decreased the oxide content) of the Ti surface during porcelain sintering, which positively affected the bond strength of Ti/porcelain (approximately 36 MPa) compared to the untreated Ti/porcelain specimen (approximately 29 MPa). The fracture morphologies of all the Ti/porcelain groups revealed an adhesive bond failure as the interfacial fracture mode between the Ti and the porcelain. CONCLUSIONS: A practical and simple sandblasting/gold sputter coating treatment of Ti surfaces prior to porcelain sintering significantly strengthens the bond between the milled, noncast Ti and the dental porcelain.
Asunto(s)
Materiales Biocompatibles Revestidos/química , Diseño Asistido por Computadora , Recubrimiento Dental Adhesivo , Materiales Dentales/química , Porcelana Dental/química , Oro/química , Titanio/química , Adhesividad , Óxido de Aluminio/química , Grabado Dental/métodos , Técnicas Electroquímicas , Calor , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oxidación-Reducción , Espectroscopía de Fotoelectrones , Docilidad , Espectrometría por Rayos X , Estrés Mecánico , Propiedades de SuperficieRESUMEN
This study investigated the bonding of dental porcelain to non-cast Ti surface with different treatments. Mechanically ground non-cast Ti strips, simulating surface conditions produced by CAD/CAM, were Al(2)O(3)-sandblasted, then subjected to different surface treatments, including immersion in HNO(3)-containing acid, NaOH-containing alkaline, and NaOH-containing alkaline then HNO(3)-containing acid. Ti-porcelain specimens preparations and their bend strength measurements were based on ISO 9693. Ti surface treatment changed not only surface roughness but also surface chemistry, leading to influence on bond strength. Bond strengths of all Ti-porcelain groups were higher than ISO 9693 minimum requirement. The sandblasted/acid-treated Ti surface showed the highest bond strength (34.60 MPa) with porcelain; no significant difference in bond strength (27.92-29.63 MPa) was found among other Tiporcelain groups. All Ti-porcelain specimens showed adhesive bond failure. Bonding between non-cast Ti and dental porcelain was strengthened by a simple and practical sandblasting/acid-etching treatment of the Ti surface prior to porcelain sintering.
Asunto(s)
Recubrimiento Dental Adhesivo , Porcelana Dental , Aleaciones de Cerámica y Metal/química , Titanio , Grabado Ácido Dental , Diseño Asistido por Computadora , Análisis del Estrés Dental , Ensayo de Materiales , Docilidad , Propiedades de SuperficieRESUMEN
OBJECTIVES: The goal of this study was to enhance the blood responses to titanium (Ti) surfaces used for dental implant application through the formation of a TiO2 nano-mesh surface layer produced by a fast electrochemical anodization treatment. MATERIAL AND METHODS: Electrochemical anodization treatments with different anodization currents and temperatures in an alkaline solution were used to create a nano-mesh oxide layer on polished Ti surface. Surface characterizations of the mesh structure were carried out using thin-film X-ray diffractometer, field-emission scanning electron microscope, and atomic force microscope. The blood responses, including the blood-clotting ability and platelet adhesion morphology, to the test Ti surfaces were evaluated. The blood-clotting ability, in terms of optical density of blood, was statistically analyzed using a nonparametric method, Kruskal-Wallis test, for the factor of anodization treatment. RESULTS: A multilayer TiO2 nano-mesh structure was rapidly formed on the polished Ti surface using a simple electrochemical anodization treatment in an alkaline solution. The TiO2 nano-mesh had an average mesh size between 34 and 93 nm, depending on the anodization current and temperature. The features on the TiO2 nano-mesh structure on the anodized Ti surface were of a similar size scale as blood proteins, giving the material better blood clot ability (P<0.05) and improved platelet activation and aggregation as compared with an untreated polished Ti surface. CONCLUSIONS: The formation of TiO2 nano-mesh on the Ti surfaces was shown to enhance blood responses, which we expect to promote cell growth in the application of dental implants.
Asunto(s)
Células Sanguíneas/fisiología , Implantes Dentales , Nanoestructuras , Titanio , Adhesión Celular , Técnicas Electroquímicas , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Estadísticas no Paramétricas , Propiedades de Superficie , Difracción de Rayos XRESUMEN
OBJECTIVE: The study was to investigate the corrosion resistance and cell adhesion of titanium (Ti) surface for dental implant application by oxygen plasma immersion ion implantation (O-PIII) treatments. MATERIALS AND METHODS: Commercially pure Ti discs (grade 2) were used as the substrate. O-PIII surface treatments, with different oxygen doses (1 × 10(16) and 4 × 10(16) ions/cm(2)), were performed in a high-vacuum chamber with a radio frequency plasma source. Atomic force microscope, X-ray photoelectron spectrometer and nanoindenter were used to analyze surface topography, chemical composition (three samples per group) and mechanical property (twenty-five samples per group) of Ti specimens, respectively. Corrosion resistance of Ti specimens (five samples per group) was evaluated by potentiodynamic polarization curve measurement in simulated blood plasma solution. The adhesion and spreading of human bone marrow mesenchymal stem cells (hMSCs) on Ti surfaces were studied. RESULTS: The results showed that O-PIII treatment had no significant influence on the surface topography of Ti specimens. The thickness of oxide layer (mainly as TiO(2)) on the O-PIII-treated Ti specimens increased with an increase in oxygen dose implanted. The O-PIII-treated Ti specimens possessed higher surface hardness and Young's modulus than the untreated Ti specimen. Potentiodynamic polarization tests revealed that the O-PIII-treated Ti surfaces had lower corrosion rate (I(corr)) and passive current (I(pass)) than the untreated Ti surface. The adhesion and spreading of hMSCs on Ti surfaces were improved by O-PIII treatment. CONCLUSIONS: O-PIII treatment could enhance the corrosion resistance and cell adhesion of Ti surface for dental implant application due to the increase in surface thickness of Ti-oxides (mainly as TiO(2)) on Ti.
Asunto(s)
Adhesión Celular/fisiología , Técnicas Electroquímicas , Iones/química , Células Madre Mesenquimatosas/fisiología , Oxígeno/química , Titanio/química , Corrosión , Dureza , Humanos , Ensayo de Materiales , Microscopía de Fuerza Atómica , Estadísticas no Paramétricas , Propiedades de SuperficieRESUMEN
The purpose of this study was to evaluate the fracture resistance of Nd:YAG laser-welded cast titanium (Ti) joints with various clinical thicknesses and welding pulse energies. A four-point bending test was used to assess the effects of various specimen thicknesses (1-3 mm) and welding pulse energies (11-24 J) on the fracture resistance of Nd:YAG laser-welded Ti dental joints. Fracture resistance was evaluated in terms of the ratio of the number of fractured specimens to the number of tested specimens. As for the fracture frequencies, they were compared using the Cochran-Mantel-Haenszel test. Morphology of the fractured Ti joints was observed using a scanning electron microscope. Results showed that decreasing the specimen thickness and/or increasing the welding pulse energy, i.e., increasing the welded area percentage, resulted in an increase in the fracture resistance of the Ti joint. Where fracture occurred, the fracture site would be at the center of the weld metal.
Asunto(s)
Materiales Biocompatibles/química , Soldadura Dental/métodos , Titanio/química , Rayos Láser , Ensayo de Materiales/métodos , Estrés Mecánico , Resistencia a la TracciónRESUMEN
In this study, the cracking susceptibility and fatigue behavior of Nd:YAG laser-welded cast Ti joints (welding pulse energy: 11, 15, and 18 J) in fluoride-containing (0 and 0.5% NaF) artificial saliva were evaluated using constant elongation rate test (CERT) and fatigue test (FT), respectively. Both CERT and FT were also carried out in open air as controls. Results showed that increasing the welding energy increased the elongation and fatigue life, but decreased the tensile strength, of cast Ti joints in open-air environment. With a welding energy of 11 J, the fluoride ions in the artificial saliva increased the cracking susceptibility and decreased the fatigue life of Ti joints. When the welding energy exceeded 15 J, the presence of fluoride ions still increased the cracking susceptibility, but did not reduce the fatigue life of Ti joints. Rupture of Ti joints--if it occurred--occurred only at the welded metal (versus the non-welded part).
Asunto(s)
Cariostáticos/efectos adversos , Soldadura Dental/métodos , Fluoruros/efectos adversos , Rayos Láser , Titanio/efectos de la radiación , Saliva Artificial/química , Resistencia a la Tracción , Titanio/químicaRESUMEN
The purpose of this study was to investigate the variation in corrosion resistance of commercial stainless steel (SS) brackets with different brands and types for the same application, using the electrochemical technique. The linear polarization test was used to evaluate the corrosion resistance, in terms of polarization resistance (Rp), of as-received commercial SS brackets in acidic artificial saliva. A two-way analysis of variance was used to analyze the Rp with the factors of brand and type. A scanning electron microscope and an atomic force microscope were used to analyze the surface morphology and roughness, respectively. The X-ray photoelectron spectroscopy was used to identify the chemical composition of the passive film on SS brackets. Results showed that different brands of SS brackets had a statistically significant difference in Rp (P < .0001), whereas there was no statistical difference between the bracket types ("Roth" and standard) (P = .27). Different surface topography, including surface roughness and defect, was present among the tested SS brackets. The same passive film structure, containing Cr2O3/Fe2O3 with small amounts of NiO, was observed on all SS brackets. The surface topography of the commercial SS brackets with identical surface passive film structure did not correspond with the difference in corrosion resistance.