CHUN-PIN LINChou H.-G.Kuo J.-C.Lan W.-H.2021-07-262021-07-2619980099-2399https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032174361&doi=10.1016%2fS0099-2399%2898%2980152-0&partnerID=40&md5=778aaeabfbf300486a8206ed8ac06c60https://scholars.lib.ntu.edu.tw/handle/123456789/572690Ultrasonic root-end preparation techniques have recently been introduced and revolutionized the field of endodontic surgery. The purpose of this study was to compare quantitatively the quality of root-end preparation techniques prepared by a specially designed ultrasonic retrotip with those prepared in a traditional manner by a microhand-piece bur. Twenty roots with two canals and an isthmus from extracted maxillary human molars were selected for this study. After instrumentation, obturation, and root-end resection, root-end preparations were made using either an ultrasonic retrotip or a conventional microhandpiece bur. With the aid of the image processing and analysis system, the specimens were inspected under a stereomicroscope for further evaluation of the quality of the shape and size of preparation. The results of this investigation showed that the ultrasonic root-end preparations produced more conservative and less perforated cavities than those made with conventional microhandpiece bur preparations. Copyright ? 1998 by The American Association of Endodontists.[SDGs]SDG3article; comparative study; endodontics; evaluation; health care quality; human; image processing; instrumentation; molar tooth; nonparametric test; single blind procedure; standard; ultrasound therapy; Evaluation Studies; Humans; Image Processing, Computer-Assisted; Molar; Quality Assurance, Health Care; Retrograde Obturation; Root Canal Preparation; Single-Blind Method; Statistics, Nonparametric; Ultrasonic Therapyjournal article10.1016/S0099-2399(98)80152-0100232502-s2.0-0032174361