DENTAL HIGH-SPEED CUTTING OF POROUS-MACHINABLE-CERAMIC RESIN COMPOSITES AND BOVINE ENAMEL

New ceramic/resin composites were prepared by filling the intercrystal spaces of a porous-CaO.SiO2-based machinable ceramic with [methyl methacrylate (MMA) +triethylene glycol dimethacrylate (TEGDMA) + Bis-phenol A glycidyl dimethacrylate (Bis-GMA)] copolymers. The composites exhibited a hardness, smaller and analogous to that of bovine enamel. Weight-load cutting tests were performed on the composites and bovine enamel, employing diamond points driven by an air-turbine handpiece. While the applied load was increased stepwise, we measured the rotational cutting speed and the cutting volume. With the addition of the applied load, the rotational cutting speed decreased and the cutting volume increased. With incrementing applied load, the degrees of the decrease in the rotational cutting speed and the increase in the cutting volume for bovine enamel were well simulated by those for the composites. It was therefore speculated that the porous-ceramic/resin composites are suitable for typodont teeth in the dental preclinical cutting exercise, and that another potential use of the composites might be in the production of future machined dental prostheses.