Cells and Materials


Radio frequency plasma etching of a selected number of dental materials , including glass filled polymeric composites, alumina reinforced ceramic, glass ionomer, and zinc oxide eugenol enhanced microstructural detail for scanning electron microscopy analyses. All four plasmas, argon , oxygen, carbon tetrafluoride (CF4), and CF4 + 4% 0 2 , proved effective, but the latter was the most effective. The etching of all materials , except the ceramic, was accomplished by the selective removal of a polymeric component. For the glass filled composites , this involved removal of the Bis-GMA matrix resin, leaving the filler particles in relief. For a microfilled composite, excellent delineation of the microfine particles contained within the prepolymerized polymer blocks was obtained , while for a hybrid composite, delineation of a bimodal particle distribution was revealed. For glass ionomer material , plasma etching enhanced the delineation between the silica gel lined unreacted glass particles and the polyacrylate matrix, as well as clearly defining regions in the matrix that were totally polysalt in nature. For a resin filled zinc oxide eugenol material, plasma etching removed the resin, leaving behind a porous material made-up of zinc oxide particles held together in a matrix partly composed of crystallites.