Ultrasound and root canal treatment: the need for scientific evaluation.

Abstract

Summary. Ultrasound has recently been introduced into endodontics to aid in the biomechanical preparation of the root canal. Although there are numerous investigations into the clinical efficacy of the endosonic system, there has been a poor understanding of the possible role of the biophysical aspects of ultrasound. Such areas where clarification is required are the possible roles of cavitation and acoustic microstreaming together with the ‘synergistic’ effect of the combined use of ultrasound and irrigant (usually sodium hypochlorite). Furthermore the oscillation of the file within the root canal may be prone to the load applied to it and this will greatly affect its efficiency. The present article aims to clarify these areas and to provide a guide to some of the biophysical terms used within the ultrasound discipline. Further investigations are required however to understand fully the action of the instrument, and it is hoped that this article will provide a basis for a scientific appraisal of endosonics.