Effect of multi-purpose primer on bonding of acrylic resin to cast titanium and gold alloy after airborne-particle abrasion.

PURPOSE: To clarify the effect of a multi-purpose primer combining several functional monomers on two prosthodontic materials (cast titanium and a gold alloy) after airborne-particle abrasion. METHODS: Disk-shaped adherends were prepared from cast titanium (CP Titanium JIS2) and a gold alloy (Casting Gold M.C. Type IV). A silane-containing two-liquid primer (M&C primer (MC)) and two silane-free single-liquid primers (Alloy Primer (AP) and V-Primer (VP)) were used as surface-treatment agents. The shear bond strengths were determined before and after thermocycling to evaluate the adhesive durability, and the results were compared using a non-parametric statistical analysis. The effect of airborne-particle abrasion with alumina on the titanium surface was analyzed by X-ray photoelectron spectroscopy (XPS). RESULTS: There was no significant difference in bond strength between the MC and AP before and after thermocycling, whereas VP showed significantly lower values. XPS revealed that the titanium acquired hydrophilic properties after the airborne-particle abrasion. CONCLUSIONS: The novelty of this study is that it shows that the presence/absence of the silane had no effect on the bonding of cast titanium with an acrylic resin. The study also showed that the multi-purpose primer can be used without any problems with both cast titanium and gold alloy, in combination with airborne-particle abrasion with alumina.

Effect of mechanochemical surface preparation on bonding to zirconia of a tri-n-butylborane initiated resin.

This study aimed to evaluate the effect of surface preparation on bond strength of a tri-n-butylborane initiated resin (MMA-TBB) bonded to zirconia. Zirconia disks were either airborne-particle abraded with alumina or silica-coated. The disks were thereafter primed with one of the following materials: phosphate-silane (Clearfil Ceramic Primer), phosphate (Alloy Primer), or silane (ESPE Sil). The specimens were bonded with the MMA-TBB. Shear bond strength was determined both before and after thermocycling. Bond strength of unprimed zirconia (control) was not affected by the surface roughness of each adherend. Priming with phosphate was effective for bonding alumina-blasted zirconia. Priming with silane was effective for bonding silica-coated zirconia. Priming effect of the phosphate-silane was superior to that of silane alone for bonding silica-coated zirconia. Bond strength to zirconia of the MMATBB is significantly influenced by a combination of the specific functional monomer and the surface modification performed rather than the material surface roughness.

Unique Distribution of Benzodiazepine Receptors in the Brain during the First Two Years of Life.

BACKGROUND: 123I-iomazenil (IMZ) single-photon emission computed tomography (SPECT) is a tool for evaluating epileptic foci and brain damage. To apply the method to children, information regarding the age-specific expression of benzodiazepine receptors (BDZ-Rs) is required. Unfortunately, there is no information currently available for children <2 years of age. METHODS: We used IMZ SPECT once in infants aged 3-8 months and again at 2 years of age in order to describe the maturational changes in BDZ-R distribution. RESULTS: No neurological deficits were found in any of the infants at the first examination. The BDZ-Rs were more dominantly distributed in the occipital lobe than in the frontal lobe before the age of 2 years. The frontal-occipital gradients of the distribution were obvious in children <8 months of age. Magnetic resonance imaging showed a spreading of myelination toward the frontal lobes simultaneously with BDZ-R expression. CONCLUSION: Information regarding the alteration in the BDZ-R distribution pattern is useful when assessing infantile epilepsy and brain injury. The age-related pattern of BDZ-R distribution could correspond with myelination, cerebral blood flow, metabolism and behavioral development.

The influence of polymerization conditions on color stability of three indirect composite materials.

The aim of the present study was to evaluate color change and color stability against aqueous media of three indirect composite materials (Epricord, Estenia, and Twiny) that were polymerized with different systems. Disk-shaped specimens were prepared with their proprietary polymerization systems or with a metal halide light polymerization unit (Twinkle X). The specimens were then immersed in water or tea. Change in color from baseline (24 h) to 4 weeks was determined with a chromameter (ShadeEye NCC) using a white background. The L*, a*, and b* values for both states were determined, and ΔE*(ab) values were calculated. The Estenia specimens immersed in tea had significantly lower ΔL* (-7.0 to -5.6) and significantly higher ΔE*(ab) values (6.5 to 8.6) than did the Epricord and Twiny specimens, under all polymerization conditions. The results indicate that after tea immersion the Estenia material was less stable against color change than were the other two materials. The Twinkle X metal halide unit was suitable for polymerization of the three composite materials, using an exposure period of 60 s or longer.

Cooling of the epileptic focus suppresses seizures with minimal influence on neurologic functions.

PURPOSE: Focal brain cooling is effective for suppression of epileptic seizures, but it is unclear if seizures can be suppressed without a substantial influence on normal neurologic function. To address the issue, a thermoelectrically driven cooling system was developed and applied in free-moving rat models of focal seizure and epilepsy. METHODS: Focal seizures limited to the unilateral forelimb were induced by local application of a penicillin G solution or cobalt powder to the unilateral sensorimotor cortex. A proportional integration and differentiation (PID)-controlled, thermoelectrically driven cooling device (weight of 11 g) and bipolar electrodes were chronically implanted on the eloquent area (on the epileptic focus) and the effects of cooling (20, 15, and 10°C) on electrocorticography, seizure frequency, and neurologic changes were investigated. KEY FINDINGS: Cooling was associated with a distinct reduction of the epileptic discharges. In both models, cooling of epileptic foci significantly improved both seizure frequency and neurologic functions from 20°C down to 15°C. Cooling to 10°C also suppressed seizures, but with no further improvement in neurologic function. Subsequent investigation of sensorimotor function revealed significant deterioration in foot-fault tests and the receptive field size at 15°C. SIGNIFICANCE: Despite the beneficial effects in ictal rats, sensorimotor functions deteriorated at 15°C, thereby suggesting a lower limit for the therapeutic temperature. These results provide important evidence of a therapeutic effect of temperatures from 20 to 15°C using an implantable, hypothermal device for focal epilepsy.

Effect of acidic primers on adhesive bonding of tri-n-butylborane initiated adhesive resin to alumina.

The present study was conducted to evaluate the effect of acidic primers on adhesive bonding to sintered alumina. Alumina disk specimens were primed with one of the following acidic materials: Acryl Bond, All Bond II Primer B, Alloy Primer, Estenia Opaque Primer, Eye Sight Opaque Primer, M.L. Primer, MR. Bond, and Super-Bond Liquid. The disks were bonded with an adhesive resin (Super-Bond) initiated with a tri-n-butylborane (TBB) derivative, and bond strengths were determined. Average bond strength before thermocycling varied from 42.9 to 44.3 MPa, whereas post-thermocycling bond strength ranged from 22.0 to 42.8 MPa. Of the nine groups assessed, reduction of bond strength after thermocycling was not significant in three: Alloy Primer, Estenia Opaque Primer, and Eye Sight Opaque Primer. It can be concluded that phosphate-based primers are recommended for bonding sintered alumina with Super-Bond resin.

Effect of alumina air-abrasion on mechanical bonding between an acrylic resin and casting alloys.

This study examined the effect of alumina air-abrasion with different pressure on bonding between an acrylic resin and casting alloys. Disk specimens (8 and 10 mm in diameter) were cast from a silver-palladium-copper-gold (Ag-Pd-Cu-Au, Castwell M.C.12) alloy and a titanium-aluminum-niobium alloy (Ti-6Al-7Nb, T-Alloy Tough). The disks were air-abraded with alumina particles (50-70 microm) under different air-pressures (0 unabraded, 0.1, and 0.6 MPa). The disk pairs were bonded together with a tri-n-butylborane (TBB)-initiated acrylic resin, and shear bond strengths were determined both before and after thermocycling. Bond strength varied from a maximum of 37.1 MPa to a minimum of 3.6 MPa for the Ag-Pd-Cu-Au alloy, whereas bond strength to Ti-6Al-7Nb alloy ranged from 34.7 MPa to 0.1 MPa. Specimens abraded with 0.6 MPa pressure recorded the greatest post-thermocycling bond strength (21.7 MPa and 17.9 MPa), and unabraded specimens showed the lowest strength (3.6 MPa and 0.1 MPa) for both alloys. Post-thermocycling bond strength to the Ag-Pd-Cu-Au alloy was higher than that to the Ti-6Al-7Nb alloy under identical air-abrading conditions. It can be concluded that alumina air-abrasion with an air-pressure of 0.6 MPa is effective in enhancing retentive characteristics of the TBB-initiated resin joined to the alloys.

Effect of single-liquid acidic primers on bonding of a composite luting agent joined to a prefabricated alumina coping material.

PURPOSE: The aim of this study was to assess the effect of acidic primers on adhesive bonding to prefabricated alumina material designed for fixed restorations. METHODS: High-purity alumina disks (Procera AllCeram) were primed with one of the following materials: Acryl Bond, All Bond II Primer B, Alloy Primer, Estenia Opaque Primer, M.L. Primer, MR. Bond, and Super- Bond Liquid. The specimens were bonded with a dualpolymerizing luting composite (Variolink II). Unprimed specimen was prepared as the control. Bond strengths were determined both before and after thermocycling. RESULTS: Average bond strength before thermocycling ranged from 12.0 to 39.1 MPa, whereas average bond strength after thermocycling varied from 0.0 to 26.9 MPa. The statistically highest post-thermocycling bond strength was obtained with the use of the Alloy Primer, Estenia Opaque Primer, and M.L. Primer agents. CONCLUSION: It can be concluded that the use of either the Estenia or Alloy Primer material, which contain 10- methacryloyloxydecyl dihydrogen phosphate (MDP), or the M.L. Primer, which contains 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA), is recommended for bonding the Procera alumina copings with the Variolink II composite.

Effects of alumina air-abrasion and acidic priming agents on bonding between SUS XM27 steel and auto-polymerizing acrylic resin.

The purpose of this study was to evaluate the effects of functional monomers contained in the primers, as well as alumina particle abrasion on bonding between stainless steel and acrylic resin. SUS XM27 steel was primed with one of the following materials; Alloy Primer, Estenia Opaque Primer, M. L. Primer, and Super-Bond Liquid. Steel disks were either ground flat or alumina-blasted, primed with one of the four agents, and bonded with an acrylic resin (Unifast Trad). Bond strength was determined both before and after thermocycling (2,000 or 20,000 cycles). Among the four priming agents, the Alloy Primer and Estenia Opaque Primer, both of which contain 10-methacryloyloxydecyl dihydrogen phosphate (MDP), exhibited better bonding performance than the others. Alumina air-borne particle abrasion considerably improved the durability of bonding between the steel and the resin material. It can be concluded that alumina blasting followed by priming with an MDP agent is recommended for bonding the resin and SUS XM27 steel.

Effect of single-liquid priming agents on adhesive bonding to aluminum oxide of a methacrylic resin.

The purpose of this study was to evaluate the effects of acidic primers on adhesive bonding to sintered aluminum oxide (alumina). Alumina disks were primed with one of the following materials: Acryl Bond, All Bond 2 Primer B, Alloy Primer, Estenia Opaque Primer, Eye Sight Opaque Primer, M.L. Primer, MR. Bond, and Super-Bond Liquid. Specimens were then bonded with an acrylic resin initiated with partially oxidized tri-n-butylborane (TBBO), and bond strengths were determined. Unprimed specimen was employed as the control. Average bond strength before thermocycling ranged from 20.5 to 41.9 MPa, whereas post-thermocycling bond strength ranged from 0.0 to 40.0 MPa. Of the eight primers, Estenia Opaque Primer and Alloy Primer showed better adhesive performance than the other materials. It could thus be concluded that either Estenia Opaque Primer or Alloy Primer--which contained an adhesive monomer, 10-methacryloyloxydecyl dihydrogen phosphate (MDP)--was recommended for bonding alumina with TBBO-initiated resin.