Evaluation of the Number of Canals Modeled With Prodesign M Files Up to Their Fracture in “Ex Vivos” Lower Teeth”

Abstract

This work aimed to evaluate the number of canals modeled with ProDesign M (PDM) files until their fracture in mandibular premolars "ex vivo". An "ex vivo" experimental study was carried out on 40 extracted lower premolar teeth with similar curvatures, containing a single canal in each tooth. An endodontic opening was made on the occlusal surface of each dental element. The selected teeth were intact and healthy. Elements with endodontic treatment, with calcified canal and with accentuated curvature were excluded from the research. Initially, the dental elements were numbered from 1 to 40, the radiographic image of each canal was obtained and they were identified with the respective numbers. Two sets of PDM file instruments were used, each containing three files: 15/05, 25/01 and 25/06, 25 millimeters long. The preparation sequence was 6/25 up to 3 millimeters below the Apparent Tooth Length (CAD), simulating the Exploration Working Length (CTEx). After that, the sequence of files 25/01, 15/05 and 25/06 continued until the tip of each instrument passed one millimeter beyond the apical foramen. After using each file, it was visually evaluated with a millimeter ruler (Dia