[High-frequency dental surgery near metal reconstructions].

: Dental electrosurgery carries the risk of incidental contact between the active electrode and metallic restorations. So far, on-line measurements of basic physical parameters during dental electrosurgery have not been performed under realistic conditions. The aim of our experimental study in pig jaws was to describe the physical phenomena more closely. 86 teeth in the jaws of freshly slaughtered pigs received occlusal amalgam fillings. Using 3 different units electrosurgical procedures were performed adjacent to the fillings. Voltage, current, impedance and power output were registered using a computer-controlled measuring system with high temporal resolution and broad dynamic range. The impedances of the amalgam fillings ranged from 0.5 to 9 k omega, with half of them being in the lower range of 0.5 to 1.5 k omega. During contact to amalgam fillings the dental electrosurgical unit had a high power output. Contact to fillings with low impedance yielded a power output up to 50 W. The other two electrosurgical units were equipped with different power output control systems thus preventing high power output during contact to metallic restorations. In conclusion, dental electrosurgery should be improved by units with dynamic power output control.