ULTRASONIC IMPLANTATION OF CALCIUM METASILICATE GLASS PARTICLES INTO PMMA

Polymer materials for clinical applications should be bioactive and ha ve a bone-bonding ability. In order to provide poly(methyl methacrylat e) (PMMA) with bioactivity, granules (<45 mu m) of a bioactive glass 5 0CaO . 50SiO(2) (mol %) were implanted into PMMA: they were suspended together with a piece of PMMA in a 40 tetrahydrofuran-60 ethanol (vol %) solution and ultrasonically agitated. The granules of <10 mu m in s ize were impregnated at similar to 40-20 mu m depth below the substrat e surface. Two types were detected on the PMMA surface: (a) a glass-gr anule layer on PMMA, and (b) an inner granule layer, a PMMA layer, and an outer granule layer on the PM MA. The bioactivity of the implanted PMMA substrates was examined in vitro with a simulated body fluid (Ko kubo solution). Apatite was precipitated on all glass granules and the whole substrate surfaces within 1 d. After 4 h soaking in the Kokubo solution, aggregates of apatite particles appeared on the substrate su rface, independently of those on the glass granules, and they grew and proliferated on the whole subtrate surface in 7 d. Silica gel islands on PM MB due to the silicate an ions from the glass were considered t o induce nucleation of the apatite particles.