Efficacy of ultrasonic cleaning.

Resin blocks conta in ing s imula ted roo t canal spaces were c o m p a r e d with ext rac ted tee th as mode ls for measu r ing the eff ic iency of endodon t i c d e b r i d e m e n t with hand ins t rumenta t ion , u l t rasonica t ion , or a c o m b i n a t i o n of bo th techniques . Canal spaces were filled with r ad io i so tope l aden gelatin, and the loss of radioact iv i ty was measu red af ter t rea tment . N o significant d i f fe rences in eff iciency o f d e b r i d e m e n t were obse rved in t ee th p r epa red with h a n d ins t rumen t s or ul t rasonics alone; bo th t echn iques r e d u c e d radioact iv i ty b y be tween 77% and 79~ Ul t rasonica t ion af ter hand i n s t rumen ta t i on was the mos t efficient method; it r e d u c e d radioact ivi ty in the tee th and blocks by 88% and 92%, respect ively .