title: Safety Assessment of Two Hybrid Instrumentation Techniques in a Dental Student Endodontic Clinic: A Retrospective Study.
abstract: The aim of this study was to retrospectively assess the safety potential of a hybrid technique combining nickel-titanium (NiTi) reciprocating and rotary instruments by third- and fourth-year dental students in the predoctoral endodontics clinic at one U.S. dental school. For the study, 3,194 root canal treatments performed by 317 dental students from 2012 through 2015 were evaluated for incidence of ledge creation and instrument separation. The hybrid reciprocating and rotary technique (RRT) consisted of a glide path creation with stainless steel hand files up to size 15/02, a crown down preparation with a NiTi reciprocating instrument, and an apical preparation with NiTi rotary instruments. The control was a traditional rotary and hand technique (RHT) that consisted of the same glide path procedure followed by a crown down preparation with NiTi rotary instruments and an apical preparation with NiTi hand instruments. The results showed that the RHT technique presented a rate of ledge creation of 1.4% per root and the RRT technique was 0.5% per root (p<0.05). Three stainless steel hand files separated: two in the RHT group and one in the RRT group. There was no separation of any NiTi file in any of the techniques. The use of the reciprocating and rotary technique for root canal instrumentation by these dental students provided good safety. This hybrid technique offered a low rate of ledge creation along with no NiTi instrument separation.
authors.affiliation: Dr. Coelho is Visiting Scholar, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill and Assistant Professor, Department of Endodontics, Universidade Paulista in Sorocaba, SP, Brazil; Dr. Card is Clinical Assistant Professor, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill; and Dr. Tawil is Director of Graduate Program, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill. coelho_marcelo@yahoo.com.br.
authors.forename: Marcelo Santos
authors.initials: MS
authors.lastname: Coelho
authors.affiliation: Dr. Coelho is Visiting Scholar, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill and Assistant Professor, Department of Endodontics, Universidade Paulista in Sorocaba, SP, Brazil; Dr. Card is Clinical Assistant Professor, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill; and Dr. Tawil is Director of Graduate Program, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill.
authors.forename: Steven John
authors.initials: SJ
authors.lastname: Card
authors.affiliation: Dr. Coelho is Visiting Scholar, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill and Assistant Professor, Department of Endodontics, Universidade Paulista in Sorocaba, SP, Brazil; Dr. Card is Clinical Assistant Professor, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill; and Dr. Tawil is Director of Graduate Program, Department of Endodontics, School of Dentistry, University of North Carolina at Chapel Hill.
authors.forename: Peter Zahi
authors.initials: PZ
authors.lastname: Tawil
mesh_terms: D004708:Endodontics / Q000193:education*; D004867:Equipment Design; D004869:Equipment Safety; D006801:Humans; D009532:Nickel; D012189:Retrospective Studies; D018915:Root Canal Preparation / Q000009:adverse effects / Q000295:instrumentation*; D014025:Titanium
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: clinical education; dental education; endodontics; root canal therapy