Effectiveness of rotary and hand files in gutta-percha and sealer removal using chloroform or chlorhexidine gel

• Autor(es):

  Bueno, Carlos Eduardo da Silveira (Pontifical Catholic University of Campinas. Department of Endodontics, São Leopoldo Mandic Dental Research Center. Department of Endodontics);

  Delboni, Maraisa Greggio (São Leopoldo Mandic Dental Research Center. Department of Endodontics);

  Araújo, Roberta Aranha de (São Leopoldo Mandic Dental Research Center. Department of Endodontics);

  Carrara, Hilton José (São Leopoldo Mandic Dental Research Center. Department of Endodontics);

  Cunha, Rodrigo Sanches (São Leopoldo Mandic Dental Research Center. Department of Endodontics).

• Fonte:

  Brazilian Dental Journal; volume 17, número 2, páginas 139-143. 2006.

• Assuntos:

  endodontic retreatment;

  nickel-titanium K³ rotary files;

  solvents.

• Resumo:

  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 37ºC 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.

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