Abstract
Zuolo AS, Mello JE Jr, Cunha RS, Zuolo ML, Bueno
CES. Efficacy of reciprocating and rotary techniques for
removing filling material during root canal retreatment.
International Endodontic Journal.
To compare the efficacy of reciprocating and
rotary techniques with that of hand files for removing
gutta-percha and sealer from root canals.
Methodology
The root canals of fifty-four human
extracted maxillary central incisors were cleaned and
shaped using a crown-down technique to a size 40 and
filled with gutta-percha and a zinc oxide–eugenol-based
sealer using a lateral compaction technique. Teeth
were divided into three groups according to the
technique used for removing the root filling material:
group I – Gates–Glidden burs and stainless steel hand
files up to size 50; group II – rotary technique with
NiTi Mtwo R files and additional Mtwo files to size
50, 0.04 taper; group III – reciprocating technique
with the Reciproc instrument R50, size 50, 0.05
taper. Chloroform was used as a solvent in all groups.
Teeth were then split longitudinally and photo-
graphed under 89 magnification. The images were
transferred to a computer, and the total canal space
and remaining filling material were quantified. The
ratio of remaining filling material to root canal periphery was computed with the aid of Image Tool
3.0 software. The mean percentages of remaining
filling material and time required to remove it were
compared using the Kruskal–Wallis and Mann–Whitney
tests (P < 0.05).
Results
The mean percentage of remaining filling
material was significantly higher (P < 0.05) in group
II, with Mtwo rotary files (12.17%), than in group I,
with the hand file technique (7.19%), and group III,
with Reciproc instruments (4.57%), which were sta-
tistically similar (P > 0.05). The time required to
remove filling material was significantly shorter
(P < 0.05) in group III (194 s), followed by group II
(365 s) and group I (725 s) (P < 0.05).
Conclusion
Remaining endodontic filling material
was observed on the canal walls of all teeth regardless
of the technique used. Hand files combined with
Gates–Glidden burs (group I) and the reciprocating
technique (group III) removed more filling material
from the canal walls than the Mtwo R files. The recip-
rocating technique was the most rapid method for
removing gutta-percha and sealer, followed by the
rotary technique and the hand file technique.
Keywords: nickel–titanium, Reciproc files, reciprocat-
ing motion, root canal retreatment, rotary instruments.
Received 24 July 2012; accepted 2 February 2013
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