Effects of ceramic microbeads on bonding between a zirconia framework and layered resin composite.

This study was conducted to evaluate the effects of ceramic microbeads on the bond strength between resin and zirconia. Microbeads made of zirconia (TZ) and zircon (ZS) were treated with and without hydrofluoric acid (HF). The microbeads were sintered to zirconia disks using intermediate feldspathic porcelains. Two control groups, NB (without microbeads) and AS (without porcelain and microbeads), were also prepared. All specimens were treated with a phosphate primer and veneered with a light-curing resin composite. The 24-h shear bond strengths were determined and analyzed by the Tukey-Kramer test (α=0.05, n=10). The TZ-HF specimen exhibited the highest bond strength, followed by TZ, ZS-HF, ZS, AS, and NB. Scanning electron microscopy observations revealed that the TZ-HF specimen had a complicated debonded surface, and it included microconcavities where the microbeads were detached. Sintering etched zirconia beads onto a zirconia framework with feldspathic porcelains is useful for bonding layered resin composite materials.

Effects of tetrabutylammonium dihydrogen trifluoride etchant on bond strengths of resin composites with Ti-6Al-4V and Co-Cr alloys.

PURPOSE: This study aimed at evaluating the effects of surface treatments with tetrabutylammonium dihydrogen trifluoride (TDTF) on the bond strengths of indirect resin composites with titanium-aluminum-vanadium (Ti-6Al-4V) and cobalt-chromium (Co-Cr) alloys. METHODS: Disk-shaped Ti-6Al-4V and Co-Cr alloy specimens were air-abraded with alumina, treated with an etchant (MEP) containing TDTF for 10 s (MEP10) or 30 s (MEP30), and rinsed with water. Subsequently, a primer containing 6-methacryloyloxyhexyl phosphonoacetate was applied to the surfaces, and the specimens were veneered with a light-curing indirect resin composite. Specimens without MEP were prepared as controls (no-MEP). Shear bond strengths were determined before or after 100,000 thermocycles, and the data were analyzed using the Steel-Dwass test (α = 0.05, n = 10). RESULTS: No significant difference was found in the bond strengths between the Ti-6Al-4V and Co-Cr alloys. In each metal alloy, the MEP10 and MEP30 specimens exhibited higher bond strengths than the no-MEP controls after 100,000 thermocycles. Scanning electron microscopy observations revealed that submicron-pits and crevices were formed on both the metal alloys upon applying the MEP etchant. CONCLUSION: Surface treatments with TDTF following air abrasion are useful for improving bonding durability while veneering resin composites on Ti-6Al-4V or Co-Cr alloy frameworks.

Effects of air abrasion and glow-discharge plasma treatment on bonding resin cement to ceria-stabilized zirconia/alumina nanocomposite.

The aim of this study was to evaluate the effects of air abrasion and plasma treatment on the bond strength between resin and ceriastabilized tetragonal zirconia polycrystals/alumina (Ce-TZP/Al2O3). Ce-TZP/Al2O3 specimens were ground with #1000 silicon-carbide paper, air abraded with alumina, and then exposed to glow-discharge plasma (Abrasion/Plasma). Specimens without air abrasion and/or plasma exposure were also prepared as controls (Abrasion/No plasma, No abrasion/Plasma, and No abrasion/No plasma). The specimens were bonded to resin composite disks with a self-adhesive resin cement (SA) or a luting composite containing no functional monomer (LC). Shear bond strengths were determined after 10,000 thermocycles at 4 and 60°C, and the data were analyzed by nonparametric tests (α=0.05, n=8/group). When using SA, the Abrasion/Plasma specimens exhibited the highest bond strength, followed by the Abrasion/No plasma, No abrasion/Plasma, and No abrasion/No plasma specimens. For LC, neither air abrasion nor plasma treatment exhibited any significant effect on bond strength.

Effect of tetrabutylammonium dihydrogen trifluoride treatment on durability of resin-titanium bond strengths.

This study investigated the effect of titanium surface treatment with tetrabutylammonium dihydrogen trifluoride (TDTF) on the bond between the titanium and resins for dental applications. Commercially pure titanium (cpTi) specimens were air-abraded with alumina particles, surface-treated with an etchant containing TDTF (Monobond Etch & Prime; ETCH) for 10 s (ETCH10) or 30 s (ETCH30), rinsed with water, treated with a phosphoric monomer-based primer, and bonded to an indirect resin composite. Non-ETCH-treated specimens (no-ETCH) were prepared as a control. The shear bond strengths were determined before and after 100,000 thermocycles, and the means and standard deviations for eight specimens were calculated and statistically analyzed using a non-parametric Steel-Dwass test (α = 0.05). The ETCH10 and ETCH30 specimens exhibited the highest bond strengths, which were maintained for 100,000 thermocycles, while significantly lower values were obtained for no-ETCH specimens. In conclusion, the surface treatment with a TDTF-containing etchant considerably improved the durability of the resin-cpTi bond strength. Appropriate surface treatment of cpTi should be selected for achieving longer-lasting treatments and better clinical solutions for patients.

Retention strength between veneering resin composites and laser-sintered cobalt-chromium alloy.

The purpose of the present study was to evaluate the retention strength between a resin composite veneering material and three types of cobalt-chromium (Co-Cr) alloy substrates. Co-Cr alloy specimens with 81 retention devices (LSR), with 144 retention devices (LDR), and without retention device (LN) were fabricated using a laser-sintering system. The specimens were air-abraded with alumina, conditioned with a primer [Alloy primer (AP) or M.L. primer (ML)], and veneered with a light-polymerized resin composite (Gradia). Three control groups (LSR-N, LDR-N, and LN-N) without primer were also prepared. After 20,000 thermocycles in 4 and 60 °C water, tensile retention strengths were determined using a universal testing machine. Data were analyzed by analysis of variance and a post hoc Tukey-Kramer HSD test (α = 0.05, n = 8). The highest retention strengths were obtained in LSR-AP (28.3 MPa), LSR-ML (23.3 MPa), LDR-AP (26.9 MPa), and LDR-ML (27.8 MPa), and these values were not significantly different. In the absence of a retention device, the retention strengths were significantly different in the following order: LN-N (0.1 MPa) < LN-ML (12.4 MPa) < LN-AP (20.2 MPa). The specimens without primer were significantly different in the following order: LN-N (0.1 MPa) < LSR-N (15.4 MPa), LDR-N (17.1 MPa). No significant difference was found between the numbers of retention devices, which were 81 and 144. In conclusion, the combined use of the primers and the retention devices is recommended when the laser-sintered Co-Cr alloy is veneered with the resin composite materials to maximize the retention strength.

Evaluation of five primers and two opaque resins for bonding ceria-stabilized zirconia/alumina nanocomposite.

The purpose of this study was to evaluate the effect of five primers [Super-Bond C&B Monomer (SB), Clearfil Ceramic Primer, Alloy Primer, M.L. Primer, and AZ Primer] and two undercoating opaque resins [Super-Bond C&B (S-opaque) and Ceramage Pre-opaque (C-opaque)] on the bonding of a resin composite veneering material to a ceria-stabilized tetragonal zirconia polycrystals/alumina nanocomposite (Ce-TZP/Al2O3). Disk-shaped specimens of Ce-TZP/Al2O3 were sandblasted with alumina and primed. The undercoating opaque resins and resin composites were subsequently applied to the specimen, and then light cured. After 5000 thermocycles at 4°C and 60°C, shear bond strengths were determined. Data were analyzed using analysis of variance, Tukey-Kramer honest significant difference test, and Student t test (n = 10, α = 0.05). With the exception of SB/S-opaque, all S-opaque groups exhibited significantly higher bond strengths than C-opaque groups. The use of S-opaque resin is recommended when veneering frameworks made of Ce-TZP/Al2O3.

Surface modification with alumina blasting and H2SO4-HCl etching for bonding two resin-composite veneers to titanium.

The purpose of this study was to investigate the effect of an experimental surface treatment with alumina blasting and acid etching on the bond strengths between each of two resin composites and commercially pure titanium. The titanium surface was blasted with alumina and then etched with 45wt% H2SO4 and 15wt% HCl (H2SO4-HCl). A light- and heat-curing resin composite (Estenia) and a light-curing resin composite (Ceramage) were used with adjunctive metal primers. Veneered specimens were subjected to thermal cycling between 4 and 60°C for 50,000 cycles, and the shear bond strengths were determined. The highest bond strengths were obtained for Blasting/H2SO4-HCl/Estenia (30.2 ± 4.5 MPa) and Blasting/Etching/Ceramage (26.0 ± 4.5 MPa), the values of which were not statistically different, followed by Blasting/No etching/Estenia (20.4 ± 2.4 MPa) and Blasting/No etching/Ceramage (0.8 ± 0.3 MPa). Scanning electron microscopy observations revealed that alumina blasting and H2SO4-HCl etching creates a number of micro- and nanoscale cavities on the titanium surface, which contribute to adhesive bonding.

Comparative study between laser sintering and casting for retention of resin composite veneers to cobalt-chromium alloy.

The purpose of this study was to evaluate and compare the bond strengths between resin composite veneer and laser-sintered cobalt-chromium (Co-Cr) alloy with and without retention devices (Laser-R and Laser-N respectively). Cast Co-Cr alloy with and without retention devices (Cast-R and Cast-N respectively) were also prepared for fabrication technique comparison. Disk-shaped Co-Cr alloy specimens were air-abraded with alumina and veneered with a veneering system, Estenia C&B (ES) or Ceramage (CE). After 20,000 thermocycles, tensile testing was performed. Data were analyzed by ANOVA and multiple comparison test. When no retention devices were present, no significant differences were observed between Laser-N/ES and Cast-N/ES, or between Laser- N/CE and Cast-N/CE, but ES exhibited significantly higher bond strength than CE. With retention devices, Laser-R/ES, Cast- R/ES and Laser-R/CE showed no significant differences, and their retention strengths were significantly higher than that of Cast- R/CE. Compared to cast Co-Cr alloy, laser-sintered Co-Cr alloy with retention devices provided better retention durability for resin composite-veneered prostheses.

Effect of siloxane quantity and ph of silane coupling agents and contact angle of resin bonding agent on bond durability of resin cements to machinable ceramic.

PURPOSE: The aim of this study was to measure siloxane quantity, pH value, and resin wettability on ceramics silanized by five silane coupling agents, and to test the correlation of these parameters of silane coupling agents with bond durability between a machinable glass ceramic and resin cements. MATERIALS AND METHODS: 1.5-mm-thick ceramic plates (ProCAD, Ivoclar Vivadent) were polished, cleaned, and bonded with ten combinations of five silane coupling agents (Monobond S [Ivoclar Vivadent], Rely X Ceramic Primer [3M], Clearfil Ceramic Primer [Kuraray], GC Ceramic Primer [GC], Porcelain Liner M [Sun Medical]) and two dual-curing resin cements (VariolinkII [VLII, Ivoclar Vivadent], Linkmax HV [LMHV, GC]). Their microshear bond strength was measured after 0, 10,000, and 30,000 thermal cycles. Siloxane quantity, pH value of silane coupling agents and contact angle of Heliobond (Ivoclar Vivadent) to silanized ceramic were measured using a FTIR spectrophotometer, pH-indicator strips, and a contact-angle meter, respectively. Bond strength data were analyzed by three-way ANOVA. For each cement, Pearson's correlation coefficient was calculated to analyze possible correlation between bond strength under different thermocycling conditions and absorbance peak of siloxane, pH value of silane coupling agents, and contact angle of resin to the silanized ceramic surface. RESULTS: The bond strength of ceramic was significantly influenced by the silane coupling agent and thermal cycles, not by resin cement. For both cements, only a negative correlation was found to be significant between the contact angle of resin to silanized ceramic surfaces and bond strength after 30,000 thermal cycles. CONCLUSION: The better the wettability of resin on different silanized ceramic surfaces could improve their bond durability.

Flexural strength of the joint between glass-infiltrated alumina frames and the alumina-magnesia modifier.

PURPOSE: The purpose of the present study was to evaluate the flexural strength of the joint between glass-infiltrated alumina frames and the experimental adjusting agent (MA modifier) that contains alumina and magnesia. METHODS: A commercially available adjusting agent (Optimizer), a slurry of alumina powder (Alumina modifier), and a bulk specimen (joint-free alumina) were used as controls. Beam-shaped alumina specimens were machined from an alumina block. The ends of two alumina beams were positioned at an interval of 1.0 mm and joined with each adjusting agent. The joined specimens were subjected to sintering, glass infiltration firing, glass control firing, and then a three-point bending test was carried out to evaluate the flexural strength. RESULTS: The maximum flexural strength was observed in the joint-free alumina, followed by MA modifier, Optimizer and Alumina modifier. With the exception for joint-free alumina, the failure modes after three-point bending test tended to shift from adhesive failure at substrate material-adjusting agent interface to cohesive failure within adjusting agent as the flexural strength increased. CONCLUSIONS: The use of MA modifier significantly improved the flexural strength of joined glass-infiltrated alumina frame. The MA modifier could be applied for adjusting the margin as an alternative to Optimizer when fabricating crown and bridge substructures with In-Ceram Alumina system.

The effect of magnesium oxide supplementation to aluminum oxide slip on the jointing of aluminum oxide bars.

The purpose of this study was to investigate the effect of modifying aluminum oxide slips with magnesium oxide (MgO) to create a jointing material for In-Ceram Alumina. Jointed In-Ceram Alumina bars with In-Ceram Alumina slips containing 0-1.0 mass% MgO were examined by a three-point bending test. Joint-free bars were also tested as controls. Fracture surfaces were evaluated by scanning electron microscopy. In addition, linear shrinkage and fracture toughness were assessed. The 0.3 mass% MgO group showed the highest flexural strength among the jointed groups, and there were no statistical differences between the joint-free control groups. The fracture surface of 0.3 mass% MgO group showed increased sintering densification with reduced micropore size. No linear shrinkage was observed with the addition of MgO to the alumina slip. Added MgO was also effective in boosting fracture toughness. The present findings indicate that the MgO-supplemented binding material is useful for clinical applications.

Effects of primers containing sulfur and phosphate monomers on bonding type IV gold alloy.

OBJECTIVE: The purpose of the present study was to evaluate the effect of five primers (two sulfur, one phosphate, and two sulfur-phosphate dual-function primers) on the bond strength between a self-curing luting agent and gold-copper-silver (Au-Cu-Ag) alloy. METHODS: The primers used were two sulfur primers (V-Primer and Metaltite), one phosphate primer (Epricord), and two primers which contained a sulfur monomer and a phosphate monomer (Alloy Primer and Metaltite/Epricord). The surface of Au-Cu-Ag specimens were blasted with alumina, and then bonded with acrylic rods using a tri-n-butylborane-initiated self-curing luting agent. Shear bond strengths were determined after 5000 thermocycles. An additional alumina-blasted Au-Cu-Ag alloy specimen was subjected to X-ray photoelectron spectroscopy (XPS) analysis. RESULTS: The maximum shear bond strengths were obtained with Metaltite/Epricord (29.6+/-2.3 MPa) and Alloy Primer (23.0+/-1.6 MPa), followed by Metaltite (10.3+/-4.2 MPa), V-Primer (8.9+/-0.6 MPa), Epricord (6.4+/-1.5 MPa), and No primer control (2.0+/-0.5 MPa). The XPS analysis detected six chemical elements (Au, Cu, Ag, Al, O, and C) on the Au-Cu-Ag alloy. In addition to pure Au element, the metal oxide-states of Ag2O, AgO, Cu2O, and CuO were suggested. CONCLUSION: The combined use of a sulfur monomer and a phosphate monomer significantly improved the bond strength of resin to Au-Cu-Ag alloy which should be especially significant to clinicians.

Effects of primers containing thiouracil and phosphate monomers on bonding of resin to Ag-Pd-Au alloy.

The purpose of the present study was to evaluate the effects of four experimental primers on bond strength between a self-curing luting agent and silver-palladium-gold alloy. The experimental primers were in mixed solutions of a thiouracil primer (Metaltite) and a phosphate primer (Epricord, PM, PE, or PP), which were designated as Metaltite/Epricord, Metaltite/PM, Metaltite/PE, and Metaltite/PP respectively. Three primers (Metal Primer II, V-Primer, and Alloy Primer) were also prepared as controls. Alumina-blasted metal alloys were bonded with acrylic rods. After 5,000 thermocycles, the maximum shear bond strength was obtained with Metaltite/PE (27.8+/-2.4 MPa) and Metaltite/Epricord (27.6+/-5.9 MPa), followed by Metaltite/PP, Alloy Primer, Metaltite, Metaltite/PM, Metal Primer II, V-Primer, and Epricord. PE, PM, and PP showed the lowest bond strength. Results of this study revealed that the combined use of a thiouracil monomer and a phosphate monomer improved adhesive bonding. In this light, clinicians should pay attention to the types of functional monomers dissolved in a primer when fabricating resin-bonded prostheses.

Influence of surface characteristics of four silica-based machinable ceramics on flexural strength and bond strength of a dual-curing resin luting agent.

PURPOSE: The aim of the present study was to evaluate the crystalline phase and microstructure of 4 commercial machinable ceramic blocks--Cerec Vitablocs Mark II (Vita), ProCAD (Ivoclar/Vivadent), GN-I (GC), and GNCeram (GC)--and compare flexural strength and shear bond strength between a dual-curing resin luting agent and the ceramics treated with a silane coupling agent. MATERIALS AND METHODS: Specimens were examined using scanning electron microscopy/energy-dispersive x-ray spectroscopy, and x-ray diffractometry. Three-point bending tests were performed with polished specimens 20 mm long, 4 mm wide, and 1.2 mm thick. Two differently shaped specimens for each of the 4 machinable ceramics were treated with a silane coupling agent. The specimens were then cemented together with a dual-curing resin luting agent. Half of the specimens were stored in water at 37 degrees C for 24 h and the other half were thermocycled 20,000 times. RESULTS: Chemical composition, crystalline phase, and crystallinity were significantly different between brands. The Vitablocs Mark II material had the significantly lowest flexural strength (101.7 +/- 15.3 MPa), while the GNCeram material had the highest (174.8 +/- 10.3 MPa). The use of a silane coupling agent yielded high shear bond strength after 20,000 thermocycles (Vitablocs Mark II: 37.7 +/- 3.7 MPa, ProCAD: 41.2 +/- 3.1 MPa, GNCeram: 50.2 +/- 2.1 MPa), except with the GN-I material (23.9 +/- 4.4 MPa). CONCLUSION: It appeared that crystal distribution and particle size of leucite crystal, not crystallinity, in the feldspar glass matrix of silica-based machinable ceramics might influence the flexural strength and efficacy of a silane coupling agent in bonding between a dual-curing resin luting agent and machinable ceramics.

Shear bond strength of a new resin bonding system to different ceramic restorations.

This study evaluated the shear bond strength of a newly developed resin bonding system, including single-liquid ceramic primer and dual-cured resin luting agent, to 5 ceramic materials (feldspathic porcelain, machinable ceramic, In-Ceram Alumina, Procera AllCeram alumina, and Cercon). Ceramic specimens were cleaned with phosphoric acid, treated with primer, and bonded with a resin luting agent. Shear bond strength was determined after 24 hours of immersion in water and/or 10,000 thermocycles. There were no significant differences in bond strength before and after thermocycling for the 5 ceramic materials (P > .05). The findings indicate that the resin bonding system may offer an acceptable performance in terms of clinical success for the 5 ceramic restorations.

Effect of four silane coupling agents on bonding of two resin-modified glass ionomer cements to a machinable ceramic.

The purpose of the present study was to evaluate the effect of four silane coupling agents on the bond strength between two resin-modified glass ionomer cements and a machinable leucite glass ceramic. Ceramic specimens were ground with silicon carbide paper and cleaned with phosphoric acid. They were then conditioned and bonded with combinations of four silane coupling agents (GC Ceramic Primer, Clapearl Bonding Agent, Clearfil Mega Bond Porcelain Bonding Kit, and RelyX Ceramic Primer) and two resin-modified glass ionomer cements (Fuji Luting S and Fuji Lute). Shear bond strength was determined after 24-hour immersion in water or after thermocycling of 50,000 cycles. The results showed that every silane coupling agent significantly improved the bond strength. It was thus recommended that resin-modified glass ionomer cement be applied in conjunction with silane coupling agent when luting ceramic restorations.

Shear bond strengths of four resin bonding systems to two silica-based machinable ceramic materials.

The purpose of this study was to evaluate the bond strength between four bonding systems (GC Ceramic Primer and Linkmax HV (CP+LM), Clapearl Bonding Agent and Clapearl DC (CBA+CL), Clearfil Mega Bond Porcelain Bonding kit and Panavia F2.0 (MB+PF), and RelyX Ceramic Primer and RelyX ARC (RC+RA)) and two machinable ceramics (Vitablocs Mark II, VMII and GN-I ceramic block, GNI). Shear bond strength was determined after 24-hour immersion in water or after thermocycling of 20,000 cycles. It was found that the post-thermocycling bond strength of each bonding system to VMII was significantly higher than that to GNI. VMII showed no significant differences between CP+LM, MB+PF, and CBA+CL--the values of which were higher than that of RC+RA. Regarding GNI, CP+LM showed the greatest bond strength after thermocycling among the four bonding systems used. It was concluded that the crystalline phase of the ceramics used might have an effect on bond strength.

The physical properties of a machinable resin composite for esthetic restorations.

To investigate the pre-clinical relevancy of a machinable composite, its physical properties were evaluated and compared with a machinable ceramic and two indirect composites. A machinable resin composite (GN-I composite, CO), a machinable ceramic (GN-I ceramic, CE), and two resin composites (Artglass dentin, AG; Estenia dentin, ET) were used. Compressive strength, diametral tensile strength, flexural strength, elastic modulus, and fracture load of standardized, premolar crown-shaped specimens were determined. In terms of compressive strength, diametral tensile strength, and flexural strength, AG showed significantly lower values than the other three materials. In terms of fracture load, specimens with 1.5 mm thick wall showed a higher value than those with 1.0 mm thick wall, and the value decreased in the order of ET, CE, CO, and AG. Marginal tipping was also observed in ET and CE. Within the limits of the current study, CO showed physical properties favorable for constructing esthetic restorations.