THE EFFECT OF DENTAL PROPHYLAXIS INSTRUMENTS ON THE SURFACE-ROUGHNESSOF METALS USED FOR METAL-CERAMIC CROWNS

Prophylactic instruments may cause surface deterioration of metal crow n margins, which could cause or aid the retention and accumulation of plaque. In this investigation, highly polished metal disks of high con tent gold (RX Y), low content gold (Aspen), silver palladium (RX 91), and nickel-chrome alloy (REX III) had their surfaces tracked with an e xplorer, hand scaler, curette, and a Dentsply Cavitron instrument. The surface roughness was measured with a profilometer. The results indic ate that the high content gold was the least resistant to surface dete rioration and the ultrasonic scaler caused the most surface deteriorat ion to all the metals.