Aim To evaluate and compare the,sealing quality of hand- or vacuum-obturate
d root canals after hand preparation or hydrodynamic cleansing of root cana
ls, respectively,
Methodology After assessing root curvature, 96 single-rooted deep-frozen te
eth were divided into eight comparable groups, The root canals of four grou
ps were instrumented with the balanced force technique. The remaining unins
trumented teeth were connected to a reduced-pressure device (NIT) and the r
oot-canal system perfused with 2.5% NaOCl under alternating pressure fields
, This dissolved the pulpal tissues and removed debris from the root-canal
system. The canals of the hand-instrumented groups were obturated using the
cold lateral condensation method with guttapercha and one of four differen
t sealers (AH26, AH Plus, Apexit and Pulp Canal Sealer EWT), The teeth trea
ted with the alternating pressure device (NIT) were obturated by a vacuum o
bturation method (NIT) with the same four sealers. The quality of the coron
al seal was assessed using a dye penetration method, In order to minimize e
rrors the roots were perfused with water before exposure to the dye, under
vacuum. The teeth were then rendered transparent and the depth of penetrati
on of the dye between the wall of the canal and the obturating material was
measured with a stereomicroscope.
Results The canals cleaned and filled by NIT showed statistically significa
ntly less dye penetration than those obturated by lateral condensation (P <
0.05), Within the NIT group, Pulp Canal Sealer EWT exhibited significantly
more dye penetration than Apexit. Amongst the control lateral condensation
groups no significant differences were found between the various sealers,
Conclusions The present investigation demonstrated the validity of the NIT
obturation method in combination with commonly used root-canal sealers.