SCANNING ELECTRON-MICROSCOPY AND ENERGY-DISPERSIVE ANALYSIS OF MACHINED DENTURE BASE SURFACES

To relate the characteristics of rotary instruments to the surfaces th ey produce, acrylic resin, Molloplast B, and Novus were investigated w ith energy dispersive analysis and scanning electron microscopy (secon dary and backscatter images) before and after machining. The chemical composition of cutting instruments, material surfaces, and residues wa s identified. Machined debris embedded in Molloplast B after machining with the Molloplast stone was found to contain a mean lead content of 45%. High concentrations of barium sulphate were discovered on the ar bor band-machined surface of Novus. These differences were related to clinically appropriate instrumentation, and, therefore, biocompatabili ty studies that intimately relate to the in vivo situation should be c onsidered for new materials.