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Impact of remaining zinc oxide‐eugenol–based sealer on the bond strength of a resinous sealer to dentine after root canal retreatment
Author(s) -
RachedJunior F. J. A.,
SousaNeto M. D.,
SouzaGabriel A. E.,
Duarte M. A. H.,
SilvaSousa Y. T. C.
Publication year - 2014
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12170
Subject(s) - zinc oxide eugenol , bond strength , root canal , dentistry , nuclear chemistry , chemistry , gutta percha , materials science , medicine , composite material , adhesive , layer (electronics)
Aim To evaluate the bond strength of a resin‐based sealer ( AH P lus) to root canal dentine after the removal of a zinc oxide‐eugenol–based sealer ( E ndofill), using different retreatment techniques. Methodology The root canals of sixty‐four maxillary incisors were prepared with P ro T aper and filled with E ndofill/gutta‐percha. After thermocycling, the roots were randomly assigned according to the retreatment technique ( n = 16): (A) P roTaper, (B) P roTaper/xylol, (C) ultrasound and (D) ultrasound/xylol and according to whether an operating microscope ( OM ) was used or not ( n = 8): GI ‐ direct vision ( DV ) and GII ‐ indirect through the OM . Eight additional roots were instrumented and filled with AH P lus/gutta‐percha (control). Roots were sectioned to obtain 1‐mm‐thick slices. Slices were used in the push‐out test and in confocal microscopy. Data were submitted to anova and T ukey test (α = 0.05). Results The specimens filled under the OM (2.50 ± 0.90) had higher bond strength values of sealer to root canal walls ( P < 0.05). The control group had superior mean adhesion values (4.75 ± 1.47) that were significantly different from the others ( P < 0.05). Ultrasound/xylol (2.53 ± 1.00) was superior to ultrasound (2.23 ± 0.72) ( P < 0.05), P roTaper (2.20 ± 0.69), P roTaper/Xylol (2.12 ± 0.65), which were similar ( P > 0.05). Bond strength was different in all thirds ( P < 0.05) and decreased in the following sequence: cervical (3.19 ± 1.18), middle (2.58 ± 1.21) and apical (1.87 ± 0.68). Confocal analysis revealed residues of E ndofill in dentinal tubules when the removal protocol was carried out with P roTaper, but not from ultrasound combined with xylol. Conclusions The OM was associated with higher bond strength values for filling material to root canals. The zinc oxide‐eugenol–based sealer negatively affected the bond strength of AH Plus to root canal walls, regardless of the retreatment technique.