Effect of polymerization mode of two adhesive systems on push-out bond strength of fi ber post to different regions of root canal dentin

Abstract

Background: A few studies have investigated the effect of the activation mode of adhesive systems

on bond strength of fi ber posts to root canal dentin. This study investigated the push-out bond

strengths of a glass fi ber post to different root canal regions with the use of two adhesives with

light- and dual-cure polymerization modes.

Materials and Methods: In this in vitro study, 40 maxillary central incisors were decoronated

at cement-enamel junction with 15 ± 1 mm root length. After root canal therapy and post space

preparations, they were randomly divided into four groups. Post spaces were treated with four

different adhesives: Excite, Excite Dual cure Single Component (DSC), self-etch adhesive (AdheSE),

and AdheSE dual-cure. Then the fi ber-reinforced composite (FRC) post, Postec Plus, was cemented

with dual-cure resin cement, Variolink II. The roots were cut into three 2-mm-thick slices. Push-out

tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min. The

mode of failures was determined under a stereomicroscope. Data were analyzed by three-way

analysis of variance (ANOVA) and Tukey test was conducted to compare post hoc with P < 0.05

as the level of signifi cance.

Results: The highest bond strength was obtained for AdheSE dual-cure (15.54 ± 6.90 MPa) and

the lowest was obtained for Excite light-cure (10.07 ± 7.45 MPa) and only the bond strength

between these two adhesives had signifi cant difference (P = 0.02). Bond strength decreased from

the coronal to the apical in all groups and this was signifi cant in Excite (group 1) and AdheSE

(group 3) (P < 0.001). In apical regions, bond strength of dual-cure adhesives was signifi cantly

higher than light-cure adhesives (P < 0.001).

Conclusion: Push-out bond strength of fi ber post to different regions of root canal dentin was

affected by both adhesive systems and their polymerization modes.

Key Words: Adhesive, bond strength, fi ber post, polymerization mode