title: Effectiveness of rotary and hand files in gutta-percha and sealer removal using chloroform or chlorhexidine gel.
abstract: The purpose of this study was to assess in vitro the efficacy of nickel-titanium K3 rotary files and hand files for removal of gutta-percha and sealer from obturated root canals using either chloroform or chlorhexidine as solvents. Sixty extracted single-rooted bovine teeth with straight, large canals were prepared, obtured and randomly assigned to 3 groups (n=20). The teeth were stored at 37 degrees C for 1 month and then the gutta-percha and sealer were removed using different techniques, as follows. Group I: size 3 Gates-Glidden drills plus size 30 hand K-files and Hedström files and chloroform; Group II: K3 NiTi rotary files and chloroform; and Group III: K3 NiTi rotary files and 2% chlorhexidine gel. Radiographs were taken and scanned and the images were digitized. The total area of the canal and the area with remaining obturation material were measured in millimeters using a computed image analysis system (ImageLab). Data were analyzed statistically by one-way ANOVA and Tukey test at 5% significance level. The groups differed statistically (p<0.05) with respect to the average percentage of remaining gutta-percha and sealer, presenting the following sequence of effectiveness (from most to least effective): Group I (15.48%), Group II (28.42%) and Group III (35.96%). The findings of this study showed that, despite the technique used for removal of filling material, none of the retreated canals were completely free of gutta-percha and sealer remnants. The use of stainless steel hand files resulted in a lesser amount of filling debris than the use of nickel-titanium rotary instruments.
authors.affiliation: Department of Endodontics, Pontifical Catholic University of Campinas, Campinas, SP, Brazil. carlosesbueno@terra.com.br
authors.forename: Carlos Eduardo da Silveira
authors.initials: CE
authors.lastname: Bueno
authors.forename: Maraisa Greggio
authors.initials: MG
authors.lastname: Delboni
authors.forename: Roberta Aranha
authors.initials: RA
authors.lastname: de Araújo
authors.forename: Hilton José
authors.initials: HJ
authors.lastname: Carrara
authors.forename: Rodrigo Sanches
authors.initials: RS
authors.lastname: Cunha
mesh_terms: D000818:Animals; D002417:Cattle; D002710:Chlorhexidine / Q000494:pharmacology*; D002725:Chloroform / Q000494:pharmacology*; D006171:Gutta-Percha; D019233:Retreatment / Q000379:methods; D012387:Root Canal Filling Materials; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D012997:Solvents / Q000494:pharmacology*
chemical_list: D012387:Root Canal Filling Materials; D012997:Solvents; D002725:Chloroform; D006171:Gutta-Percha; D002710:Chlorhexidine