The size of root systems has been studied extensively and described by Weaver (1920, 1926), Weaver and Bruner (1927), and others in the United States and by Kutschera (1960) in Europe. However, the physiology of roots received lessattention until recently, at least partly because they are usually underground and more difficult to study. Nevertheless, even casual consideration of their functions...

background: root canal cleaning is an important step in endodontic therapy. in order to develop better techniques, a new generation of endodontic instruments has been designed. the aim of this study was to compare the effectiveness of manual k-files (mani co, tokyo, japan) and two rotary systems–mtwo (dentsply-maillefer, ballaigues, switzerland) and protaper (vdw, munich, germany)–for root cana...