The invention relates to an ultrasonic tip and modelling pliers used in dental medicine, in the microsurgical technique of the endodontic retreatment, namely the retrograde preparation of the root canal on a length of more than 3 mm. The claimed tip is made of a controlled shape memory Nickel-Titanium alloy and has an internal thread (e) which may be screwed, using a universal key, into an ultrasound apparatus, a passive part (c), exterior to the thread, provided with two grooves (d) in which the key is positioned, the passive part (c) is continued with a rod (b) with a length ranging between 19...25 mm, whose active part (a) of at least 5 mm is hexalobe-shaped and the convex surfaces (a) can be covered with abrasive powder, the passive part (c) and the rod (b) having at the inside, along the entire length, a channel (f) ensuring an optimal irrigation with the role of cooling, disinfecting and increasing the efficiency of removing debris and residues from the root canal. The claimed modelling pliers, which can bend the tip depending on the topography of the tooth to be treated, are made of sterilizable metal or non-metal alloy and have two arms, one with prominences of various diameters, with the appearance of a quarter of a sphere, the homologous arm being the negative replica of the other arm, and both arms ending at their tips with a triangular nose, all this configuration being covered with a silicone material.Invenţia se referă la o ansă ultrasonică şi la un cleşte modelator, folosite în medicina dentară, în tehnica microchirurgicală a retratamentului endodontic, respectiv, la prepararea retrogradă a canalului radicular pe o lungime mai mare de 3 mm. Ansa conform invenţiei este confecţionată dintr-un aliaj Nichel - Titan cu memorie controlată, şi are o porţiune cu filet (e) interior care se poate înfileta cu o cheie universală, la un aparat ultrasonic, o parte (c) pasivă, exterioară filetului, prevăzută cu două şanţuri (d) în care se poziţionează cheia, part
