SELECTIVE INTERFERENCE WITH PACEMAKER ACTIVITY BY ELECTRICAL DENTAL DEVICES

Objective. We sought to determine whether electromagnetic interference with cardiac pacemakers occurs during the operation of contemporary e lectrical dental equipment. Study Design, Fourteen electrical dental d evices were tested in vitro for their ability to interfere with the fu nction of two Medtronics cardiac pacemakers (one a dual-chamber, bipol ar Thera 7942 pacemaker, the other a single-chamber, unipolar Minix 83 40 pacemaker). Atrial and Ventricular pacemaker output and electrocard iographic activity were monitored by means of telemetry with the use o f a Medtronics 9760/90 programmer. Results. Atrial and ventricular pac ing were inhibited by electromagnetic interference produced by the ele ctrosurgical unit up to a distance of 10 cm, by the ultrasonic bath cl eaner up to 30 cm, and by the magnetorestrictive ultrasonic scalers up to 37.5 cm. in contrast, operation of the amalgamator, electric pulp tester, composite curing light, dental handpieces, electric toothbrush , microwave oven, dental chair and light, ENAC ultrasonic instrument, radiography unit, and sonic scaler did not alter pacing rate or rhythm . Conclusions. These results suggest that certain electrosurgical and ultrasonic instruments may produce deleterious effects in medically fr agile patients with cardiac pacemakers.