... introduced and evaluated rather than thepreparation protocol as suggested by the manufac-turer. This might result in inadequate use ofinstruments and techniques and lead to misleadingresults and ... taper and flow, and main-tenance of original canal shape, i.e., to record thedegree and frequency of straightening, apical transpor-tation, ledging, zipping and the preparation ofteardrops and ... (13, 65, 66) and horizontal (67–69) sections ofextracted teeth. In horizontal sections remainingpredentine, pulpal tissue and debris may be stained and the amount of remaining tissue and debrismeasured...