Effectiveness of a hand file and three nickel-titanium rotary instruments for removing gutta-percha in curved root canals during retreatment.
OBJECTIVE
This study intended to compare the effectiveness of hand files and FlexMaster, ProTaper, and RaCe rotary instruments for removing gutta-percha in curved root canals during retreatment.


METHODS
Sixty curved mandibular premolars were randomly divided into 4 groups of 15 specimens each. The canals were enlarged and obturated using lateral condensation technique. After repreparation with the test instruments the specimens were cleared. The area of remaining obturation material was measured from 2 directions. Statistical analysis was performed using the Kruskal-Wallis test and a closed test procedure.


RESULTS
RaCe instruments revealed significantly less residual obturation material than FlexMaster files (P < .05). No significant difference was found among the hand file, ProTaper, and FlexMaster groups (P > .05). There were 5 fractured instruments in the ProTaper group and 3 in the FlexMaster group.


CONCLUSIONS
The RaCe system is an efficient and safe device for gutta-percha removal in curved root canals.
Schirrmeister
Jörg F
JF
Department of Operative Dentistry and Periodontology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany. joerg.schirrmeister@uniklinik-freiburg.de
Wrbas
Karl-Thomas
KT
Schneider
Felix H
FH
Altenburger
Markus J
MJ
Hellwig
Elmar
E
D001641:Bicuspid; D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D004867:Equipment Design; D004868:Equipment Failure; D004869:Equipment Safety; D005119:Extravasation of Diagnostic and Therapeutic Materials; D006171:Gutta-Percha; D006801:Humans; D009532:Nickel; D019233:Retreatment; D012387:Root Canal Filling Materials; D018915:Root Canal Preparation / Q000295:instrumentation*; D018709:Statistics, Nonparametric; D014025:Titanium
D003722:Dental Alloys; D012387:Root Canal Filling Materials; C040654:titanium nickelide; D009532:Nickel; D006171:Gutta-Percha; D014025:Titanium