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Biomedical subjects

M Atsuta

Publications and source records attributed to M Atsuta.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Properties of titanium dioxide-polymer composite with titanate coupling agents].

Titanium dioxide-polymethacrylate composites were prepared with triethyleneglycol dimethacrylate (TEGDMA), 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimeth ylexane (UDMA) and rutile structure titanium dioxide. The coupling agents used were isopropyldimethacrylisostearoyl titanate (KR7), isopropyltri (dioctylphosphate) titanate (KR12) and 4-methacryloxyethyl trimellitate anhydride (4-META). Compressive and transverse strengths of composites were determined under various experimental conditions. Compressive strength of composite with KR 7-treated titanium dioxide was higher than that with untreated titanium dioxide. Transverse strength of the composite with 4-META-treated titanium dioxide was higher than that with untreated titanium dioxide. Both compressive and transverse strengths increased when the titanium dioxide was treated with the mixture of KR7 and 4-META. Scanning electron microscopic observations of fractured composite surfaces showed titanium dioxide polymer interface failure with untreated specimens and polymer cohesive fracture with KR7 + 4-META-treated specimens. The results suggest that titanium dioxide treated with both KR7 and 4-META is useful as a pigment of the opaque material of fixed prosthodontic composite.

Composite Resins↗
PubMed1989

[Biological evaluation of biomaterials using cultured chick embryo femurs (3)].

The biological effects of adhesive resins were studied by an organ culture method using chick embryo femurs, of which usefulness was investigated to evaluate the biocompatibility of biomaterials. Superbond C & B and Panavia EX were processed to form test pieces of 0.35 mm in diameter and 2 mm in length. The test piece was inserted into the distal epiphysis of the femur, which was cultured at 37 degrees C for 7 days. The biomaterials were evaluated by relative growth rate, relative wet/dry weight ratio (W/D) and histological examination. The femurs with insertion of Superbond C & B or Panavia EX did not show growth inhibition, but W/D of Panavia EX was significantly higher than that of control. Histologically, undifferentiated cartilage cells and immature cartilage matrix were observed in the tissue adjacent to Panavia EX. These results suggested that Panavia EX had a slightly toxic effect on the chick embryo femur.

Animals↗
PubMed1988

A new ion-coating surface treatment of alloys for dental adhesive resins.

4-META and new phosphate-methacrylate resins adhere strongly to dental alloys. However, for strengthening the water durability of the adhesive interface, the oxidation of the alloy surface is indispensable. A new oxidation method using ion-sputtering was developed, and the effectiveness of this surface treatment on two dental alloys--a type IV gold alloy and Ni-Cr-Be alloy--was investigated. As an endurance test, thermocycling for a maximum of 100,000 cycles was adopted, and the tensile adhesive bond strength was then measured. Ion-coating the surface of the alloys resulted in strong bonds with adhesive resins, and after 100,000 thermocycles, a bond strength of above 20 MPa was maintained.

Adhesiveness↗
PubMed1983

Strong composites of dimethylacrylates with 4-methacryloxyethyl trimellitic anhydride.

Particles of a lithium aluminum silicate, which had been treated with a silane coupling agent, were centrifuged either in an adduct of bisphenol-A/glycidyl methacrylate (Bis-GMA) or in a mixture of Bis--GMA and methyl methacrylate. Polymerization was effected by heating with 2,5-dimethyl-hexane-2,5-dihydroperoxide. Flexural strength passed through an optimum value with increasing loading of the silicate. Inclusion of 4-methacryloxyethyl trimellitic anhydride, 4-META (5 wt % on monomer), increased the optimum flexural strength by about 20% (to 240 MPa). Evidence that 4-META increased the adhesion of filler particles to the polymeric matrix was obtained by examination of fracture surfaces.

Acrylates↗
PubMed1982

A new coupling agent for composite materials: 4-methacryloxyethyl trimellitic anhydride.

Composite materials were made by sedimention of ceramic powders in methyl methacrylate which was then polymerized by gamma-irradiation. Inclusion of 4-methacryloxyethyl trimellitic anhydride (4-META) generally was found to result in an increase in Knoop hardness number, Young's modulus, and transverse strength. Most emphasis was placed on transverse strength which was found to be increased by ca. 30% by inclusion of 4-META (5 wt %) in composites made with silanated LiAlSiO4. However an abrupt decrease in strength was found for composites with greater than ca. 83 wt % silanated LiAlSiO4. This was shown by fractography to be due to increased porosity and dewetting at the higher filler contents. Fractography also indicated that inclusion of 4-META results in a more coherent polymeric matrix. Further evidence for greater coherence was obtained by showing that 4-META confers resistance to disintegration by chloroform.

Acrylates↗
PubMed1981

4-META opaque resin--a new resin strongly adhesive to nickel-chromium alloy.

1) A new adhesive opaque resin containing a reactive monomer, 4-methacryloxy-ethyl trimellitate anhydride (4-META), was prepared, and its application to thermosetting acrylic resin veneer crowns was studied. 2) The 4-META opaque resin was applied to a variety of nickel-chromium dental alloy specimens which had undergone different treatment, and endurance tests were conducted to evaluate the durability of adhesion. 3) Stable adhesion against water penetration was achieved with metal surfaces first etched with HCl and then oxidized with HNO3. A bond strength of 250 kg/cm2 was maintained even after immersion in water at 37 degrees C for 30 wk or at 80 degrees C for ten wk. Furthermore, this value did not decrease even after the specimens were subjected to 500 thermal cycles. 4) The 4-META opaque resin studied can eliminate the necessity for retention devices on metal castings. 5) The smooth 4-META opaque resin should have no adverse effects on gingivae.

Acrylates↗