Surface texture and strength of vitreous carbon-poly(methyl methacrylate) dental implant materials

A study has been carried out on the surface texture and the strength of several dental implant materials composed of vitreous carbon microballoons (6, 24, and 48 wt %)and poly(methyl methacrylate). Two sizes of microballoons were used--particle size less than 100 micrometer and particle size greater than 100 micrometer. Square wafers of the materials (10 X 10 X 1 mm) were studied with the surface sandblasted in half of the specimens. SEM studies revealed a rough porous surface with scattered moderately sized deep cavities in the 6% and 24% specimens with an increase in the number of cavities in the 24% specimens. The 48% specimens revealed a rough, porous surface composed of large shallow craters. Prepared specimens of the materials, processed by a gas-fired air oven and by a microwave oven, were tested for compressive strength and tensile strength using an Instron Universal Testing Machine. Compressive strengths of the various mixtures were similar, but mixtures using VC particle size over 100 micrometer demonstrated somewhat reduced compressive strength. Tensile strengths of the mixutres decreased significantly as the amount of VC increased, with a 20% reduction at 24 wt % and a 45% reduction at 48 wt %.