[Extraoral accidents with endodontic rotary instruments. Report of two cases]

A serious warning against the possibility of extra-oral accidents caused by endodontic mechanically driven instruments is made. Some critical characteristics of such instruments are described, as well as physical, technical, ergonomic and human reasons conducting to these accidents, two cases of which are related. Finally, colleagues are invited to think critically upon their own rhythm of labour and some preventive measures are proposed.