Evaluation of root canal preparation with two automated endodontic handpieces.

An evaluation of automated low-speed handpiece preparation of canals was made by a silicone injection technique. These preparations were compared and rated with canals prepared by conventional hand instrumentation. Canals were graded on the criteria of shape, smoothness, elimation of morphologic aberrations, and apical preparations. Conventional hand istrumentation proved to be superior and required approximately the same amount of time as automated ins-rumentation in this vitro study.