Push-out bond strengths of endodontic posts bonded with different resin-based luting cements.
OBJECTIVE
To compare the push-out bond strengths of endodontic posts bonded with different resin-based luting cements and to verify that bond strengths did not vary with cement thickness.


METHODS
48 root canals were shaped using 6% NiTi rotary files, obturated with gutta-percha and AH Plus sealer and prepared for post cementation using Panavia F, Parapost cement, SuperBond and Unicem Rely X. All roots were sectioned into 0.7 mm thick slices and digital photographs of each slice were analyzed using Scion Image to measure the surface area of the luting cement. The root slices were stressed to failure at 1 mm/minute using a push-out test. Push-out strength was calculated as the force at failure divided by the bonded surface area. Least squares linear regression analysis was used to assess the effect of cement thickness on bond strength. Fractured specimens were further observed under the SEM.


RESULTS
Mean push-out bond strengths were: Panavia F (8.8 +/- 3.6 MPa), Parapost cement (9.1 +/- 4.4 MPa) SuperBond (14.6 +/- 2.9 MPa) and Rely X Unicem (12.4 +/- 3.3 MPa). The Panavia F and the Parapost cement were not significantly different from each other, but both were significantly lower (P < or = 0.05) than SuperBond and Rely X Unicem. Although there were large variations in cement thickness, the cementation of fiber posts with thicker cement layers did not affect the performance of the adhesive luting cements applied to root canal dentin.
School of Dental Medicine, University of Geneva, Switzerland.
Lionel
L
Huber
Maria
M
Cattani-Lorente
Ligia
L
Shaw
Ivo
I
Krejci
Serge
S
Bouillaguet
D000704:Analysis of Variance; D001840:Dental Bonding / Q000379:methods*; D006801:Humans; D016018:Least-Squares Analysis; D016014:Linear Models; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry*; D012390:Root Canal Therapy / Q000379:methods; D013718:Tensile Strength
D019279:Resin Cements