Morphological Study on the Enamel and Dentine Cut by the Powder Jet of Al₂O₃

Abstract

The purpose of this study was to examine the morphological findings of human sound and carious enamel and dentin cut by the powder jet of aluminium oxide (Al₂O₃). Twenty human permanent teeth including carious teeth, premolars and third molars, were used for this study. As a cutting device, Kinetic Cavity Preparation (KCP) -2000, which was developed by American Dental Laser Co. was used. The diameter of powders was 27 um and 50, um. The velocity of Al₂O₃ powders was 80 psi (5. 6 kg/cm₂), 120 psi (8. 4 kg/ cm₂) and 160 psi (11. 2 kg/cm₂). Keeping one or two mm distance from the tooth surface, the cavity preparation was carried out by the fine tip of 0. 34 mm in diameter. The specimens were observed by Nikon HFX-IIA and JEOL JSM-T220A SEM after the dehydration and metal coating. As a result, the discoloration on the tooth surface which was cut by KCP-2000, could not be found by the naked eye and light microscopic observation. The detail morphological findings did not depend on the size and velocity of Al₂O₃ powders, but the cavity surface showed the smooth findings like a sandy beach. Almost Al₂O₃ powders were removed by the air blast of KCP device from the cavity, but a little bit amount of powders were entered into dentinal canals and the cut surface was paved with the powders or debris. The size or morphology of these particles were irregular and variable. It was concluded that this newly developed KCP-2000 had an excellent cutting ability and could be put into the clinical dental practice.