title: Crown-down preflaring in the determination of the first apical file.
abstract: In this study, scanning electron microscopy (SEM) was used to evaluate the adaptation of the first apical file after preflaring in mesiobuccal (MB) and mesiolingual (ML) canals of mandibular molars considering the tactile sensibility as a reference. The mesial canals (n = 22) of human mandibular molar teeth were used, and the first instrument to bind to the working length was determined after preflaring and crown-down shaping. Digital images of the root apex were acquired and a single examiner determined the contact of the file with the walls using Image J software. The results showed that the file was in contact in 47.83% and 31.71% in the MB and ML canals, respectively. When the apexes are fused, the average was 40.03%. A descriptive analysis showed that the first apical file did not touch all dentin walls in any of the samples.
authors.affiliation: Department of Clinics, School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil. lfms1960@gmail.com
authors.forename: Luiz Fernando Machado
authors.initials: LF
authors.lastname: Silveira
authors.forename: Carina Folgearini
authors.initials: CF
authors.lastname: Silveira
authors.forename: Luis Antônio Suita de
authors.initials: LA
authors.lastname: Castro
authors.forename: João Batista
authors.initials: JB
authors.lastname: César Neto
authors.forename: Josué
authors.initials: J
authors.lastname: Martos
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000033:anatomy & histology*; D009811:Odontometry; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D019227:Tooth Apex / Q000033:anatomy & histology