H. Matsui

Denture base materials reinforced with glass cloths: bending property and adhesivity

The reinforcement with glass cloth to a heat-curing base resin was studied using 11 kinds of glass cloths. The bending strength was improved by some glass cloths. The scanning electron microscope observation showed that the adhesivity of the interface between glass fibre and base resin was better for the composite resin containing twill weave than for some others with plain weave. The coating treatment of glass cloth tends to give the base resin a stronger bending strength than those of the composite resins composed of non-treated glass cloths.

Denture base materials reinforced with glass fibres: Part 2The effect of glass fibre contents on bending properties

A study on laying glass fibres with different aspect and volume ratios into denture base resin is presented. Increased strength and toughness are found for the composites containing glass fibres with higher ratios. Their characteristics have prompted the inclusion of surface treated glass fibres in denture materials.

Dental application of glass cloth to denture: dimensional accuracy in reinforced resins

Duplicate dentures were made from heat-cured (HC) and microwave-cured (MC) bases, and with these bases reinforced with glass cloth. The clearance as a dimensional change in the resins was measured in relation to duplicate gypsum models from a master denture model. The clearance value in resins stored in distilled water at 37°C demonstrated better dimensional accuracy as compared with base resin replicas stored in air at 37°C. When measured at 1 kg load, MC and HC base resins showed a decrease in the clearance value. MC and HC resins reinforced with glass cloth had no significant difference between the values of dimensional accuracy at each site. The MC base and reinforced resins could be useful, comparable with HC acrylic base resin, for dental applications.

A thermoanalytical study on non-asbestos ring-lining materials for dental application

New non-asbestos papers composed of glass fibres and ceramic fibres were used as asbestossubstitute casting-ring liners in the dental field. The lining materials showed a softening temperature higher (above 800°C) than the furnace temperature. As far as the accuracy due to dimensional changes is concerned, new ring-lining materials such as glass fibre (paper and twill) and ceramic fibre have an effect similar to that of a conventional asbestos paper, indicating that non-asbestos liners could be advantageous.

An application of non-asbestos papers to the dental field: mechanical properties and structural change

New non-asbestos papers composed of glass fibres and ceramic fibres were examined for dental application. The fibre liners showed a larger deformation ability than conventional asbestos paper, and had a smaller water uptake than the conventional liner. In addition, the setting expansion in new non-asbestos papers was increased at 60 min after investing, similarly to the setting expansion behaviour in a conventional liner. After casting a silver alloy using the new fibre liners, a microstructure mainly of primary solid formed, with a smaller amount of complex phases. The microstructures formed were similar to those in the conventional asbestos liner.

Effect of storage condition on dimensional change in microwave curing resin including a twill glass cloth

As acrylic base resin was improved by only minor modification due to the use of reinforcing material, the fibred resins could be attractive in the dental field. The dimensional change has been frequently calculated by the clearance between the denture base resin and the model. The value in microwave curing (MC) fibred resin reinforced with a twill glass cloth was examined to clarify the effect of the storage conditions

An application of monomer coating for glass-cloth-reinforced acrylic resin

This work was designed to study the application of monomer-coated glass cloths to denture base heat-curing acrylic resin, and the improvement of the bending properties and impact energy in the reinforced resins was attempted by including glass cloth with a twill weave treated by multifunctional monomers. The results, that true adhesion between fibre and resin matrix occurs, support the increases in mechanical properties when treated with the heat-cured monomer. A remarkable increase in impact energy rather than maximum strength as a bending strength was achieved in the reinforced specimen including the twill-woven glass cloth treated due to the multifunctional monomers, and the energy value in the multifunctional-treated specimen was almost twice that in the plain acrylic resin.

Adaptability in visible-light-cured resins reinforced with glass cloth

The visible-ligth-cured (VCL) resin triad was cured after adding the reinforcing material to the VCL base resin. Because VCL fibred resin was improved by reinforcement of glass linear fibre or kevlar fibre, the enhancement of mechanical properties by these fibres was larger thanthose of unreinforced materials

Fibre reinforcement in heat-cured, microwave-cured and visible light-cured base resins

The mechanical properties at transverse deflection, bending and impact tests were examined in three fibre reinforced resins including reinforcing materials such as inorganic glass fibre and cloth, organic Kevlar fibre and combined fibres. Both heat-cured and microwave-cured reinforced materials had almost the similar pattern to the changes in the mechanical properties, as compared with those in visible light-cured reinforced resin. Their reinforcing materials increased modulus and impact energy by about two times as compared with the bases. The visible light-cured resin was, however, not effective as a base resin when reinforced with fibres tested here, indicating that the transverse deflection and modulus values in light-cured reinforced resin were similar to that in the plain base resin.

Dental application of various kinds of fibres in heat curing acrylic resin

The effect of the type of fibres on bending behaviour and impact energy in reinforced acrylic resin was examined. Reinforcing materials such as inorganic glass fibre and cloth and organic polyester and Kevlar fibres were coated with a silane coupling treatment, whereas Co-Cr wire was directly used for the reinforcement. After silane coupling treatment each fibre was added to the heat curing base resin, except polyester fibre. It is concluded that the inclusion of glass linear fibre provides an effective improvement on plain acrylic base resin. An additional way to reinforce the resin matrix was given by the combined use of glass and Kevlar fibres.