04-12-2012, 05:12 PM
Effectiveness of ProTaper, D-RaCe, and Mtwo retreatment files with and without supplementary instruments in the removal of root canal filling material
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Abstract
Marques da Silva B, Baratto-Filho F, Leonardi DP,
Henrique Borges A, Volpato L, Branco Barletta F. Effectiveness
of ProTaper, D-RaCe, and Mtwo retreatment files with and
without supplementary instruments in the removal of root canal
fillingmaterial. International Endodontic Journal, 45, 927–932, 2012.
Aim To assess the efficacy of different retreatment
rotary files in removing gutta-percha and endodontic
sealer from canals.
Methodology Ninety straight single-rooted premolars
were prepared up to a size 30 and filled with guttapercha
and sealer and then randomly assigned to six
retreatment groups (n = 15). Groups I, III, and V were
retreated using rotary systems ProTaper Universal
Retreatment (PTUR), D-RaCe, and Mtwo Retreatment,
respectively. Groups II, IV, and VI were retreated using
the additional instruments F4,
Introduction
Although root canal treatments have a high success
rate of more than 90% when properly conducted (Kim
& Kratchman 2006), failures may occur that are often
associated with poorly treated canals (Mollo et al.
2011). Problems related to canal anatomy (Torabinejad
et al. 2009) and also microbial factors can explain
failure rates of around 8% for treated canals (Masiero &
Barletta 2005).
Material and methods
After ethics committee approval, 90 single-rooted
straight premolar teeth with fully formed apices and
no calcifications or internal resorption were used. To
standardize the cohort, the crowns were removed to
leave a 21-mm root.
A single operator prepared root canals in a step-down
sequence (Goerig et al. 1982). The cervical and middle
thirds were enlarged using Gates Glidden burs sizes 1, 2,
and 3 (Dentsply Maillefer, Ballaigues, Switzerland). The
apical third was prepared up to a size 30 K-type file
(Dentsply Maillefer), and the middle and cervical thirds
were flared and refined with size 55 K-type files
(Dentsply Maillefer) used to the length of the Gates
Glidden bur no 1 minus 1 mm. At each instrument
change, the root canal was irrigated with 2 mL of a 2.5%
NaOCl solution delivered using a syringe with a 27-
gauge needle (Ultradent, South Jordan, UT, USA). When
root canal instrumentation was completed,
Results
All teeth had filling material remnants in the canal,
except for two teeth in group II, two teeth in group IV,
and one tooth in group VI. Table 2 shows the averages
of the area of residual filling material to the area of root
canals after instrumentation for each group.
Analysis of the total area revealed the least remaining
material in groups I, II, IV, and VI. The amount of
material was significantly different when compared to
groups III and V. In the groups with additional
instrumentation, no statistical differences were found.