title: Extrusion of debris after use of rotary nickel-titanium files with different pitch: a pilot study.
abstract: The aim of this investigation was to quantitatively compare the amount of debris extruded apically from curved canals when using rotary nickel-titanium files with different pitches and sequences of use under the same preparation technique. Thirty-six extracted human maxillary and mandibular molars with curved root canals were used. They were divided into two groups of 18 teeth each prepared by one of two different sequences with NRT files (MANI Inc., Tochigi, Japan). Each group was further divided into three subgroups according to file pitch length (short, medium and long). The debris extruded apically was collected in glass vials. The liquid inside was dried and the debris in each group was weighed and compared. Two-way analysis of variance and Fisher's PLSD test were used to evaluate differences between the extruded debris weights among the experimental groups. No statistically significant difference was observed between two sequences. There were significant differences in sequence 1 between the short pitch group and the others. Also, there were significant differences between the long pitch and others in sequence 2, except between the short and medium pitches. In conclusion, short pitch design resulted in significantly less amount of debris extrusion compared with the other pitch lengths.
authors.affiliation: Pulp Biology and Endodontics, Department of Restorative Sciences, Tokyo Medical and Dental University, Tokyo, Japan. elhamdent@msn.com
authors.forename: Elham A
authors.initials: EA
authors.lastname: Elmsallati
authors.forename: Reiko
authors.initials: R
authors.lastname: Wadachi
authors.forename: Hideaka
authors.initials: H
authors.lastname: Suda
mesh_terms: D000704:Analysis of Variance; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000601:surgery*; D004867:Equipment Design; D006801:Humans; D008334:Mandible; D008437:Maxilla; D008963:Molar; D009532:Nickel; D010865:Pilot Projects; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D016369:Smear Layer; D018709:Statistics, Nonparametric; D014025:Titanium
chemical_list: D009532:Nickel; D014025:Titanium