Flexible plastic waveguides (FPW) were devised for the delivery of Er-
YAG laser radiation, The FPW characteristics were studied under variou
s conditions. In vitro studies were carried out to explore the drillin
g procedure on extracted teeth and the FPW-tissue mutual effects, The
results which were obtained proved that the FPW as a delivery device m
ight be a substitute hand applicator for the pneumatic turbine for dri
lling in teeth.