In vitro Push-out Evaluation of Different Fiber Post Cementation Strategies

To measure push-out bond strengths (PBS) of pairs of luting systems from the same manufacturer to root dentin.

Methods: 

Dowel spaces were prepared with RelyX Fiber Post (RXP, 3M ESPE) drills in 60 endodontically-treated human monoradicular teeth. Teeth were randomly assigned to a luting system (n=10): MCO - AdheSE DC/Multicore Flow (Ivoclar Vivadent); MLI - Multilink Primer/Multilink Automix (Ivoclar Vivadent); PCO - ParaBond/ ParaCore (Coltene); PCE - ParaBond/ParaCem Universal DC (Coltene); RUL - Scotchbond Universal Adhesive (self-etch)/RelyX Ultimate (3M ESPE); RUN - RelyX Unicem 2 Automix (3M ESPE).  RXPs (3M ESPE) were used for all groups.

Roots were sectioned in three 2.0±0.1mm-thick slices: Cervical (C), Middle (M), and Apical (A). Each slice was tested in a universal testing machine at a crosshead speed of 1.0 mm/min applied to the post center until failure. PBS were calculated by dividing the minimum force for rupture the bond by the area of the interface (conical frustum). A two-way ANOVA/Fisher’s LSD multiple comparison test (p<0.05) were computed. 

Results: 

(MPa±SD)

For all root thirds, the luting systems that include a buildup composite (MCO and PCO) resulted in higher mean PBS than their counterpart luting systems that included a resin cement (MLI and PCE). The self-adhesive cement RUN and the self-etch luting system RUL resulted in similar mean PBS. MLI resulted in the lowest mean bond strength, especially at the M and A root thirds.

Conclusion: 

Buildup composite resins combined with the recommended adhesive may be used to lute fiber posts. The self-adhesive cement RUN performed at the same level as the self-etch resin cement RUL.