Bond strength according to the moment of fiber post cutting fixed with self-adhesive cement to the root dentin

The fiber posts require a cut in the coronal portion to adjust it to the available clinical space. The cutting of posts cemented may generate tension via bur vibrations of drill on the bonding interface, with the possibility of decreasing the bond strength. Thus, this study aimed to evaluate if the moment of cutting the fiber posts has an effect on its bond strength when fixed with self-adhesive resin cement.

Thirty-six bovine teeth were randomly divided into three groups after endodontic treatment and post space preparation (n = 12): IAC- the fiber posts were cutting immediately after cementation; ACR - the fiber posts were cutting after coronal reconstruction with resin; Control - the fiber posts were not cut. The fiber posts were cemented with self-adhesive cement (RelyX U200 - 3M ESPE). After 24 h, the teeth were sectioned perpendicularly and the push-out test was performed in a universal testing machine at a speed of 0.5 mm/min, until failure. Data were analyzed using two-way ANOVA and Tukey's post-hoc test.

The effect of moment of fiber posts cutting (p = 0.44) and the interaction between the factors moment of post cutting and third root (p = 0.81) had no significant. The root third factor showed a significant effect (p = 0.01). The bond strength in the apical third was significantly lower than in the middle (p = 0.00) and coronal (p = 0.01) thirds.

The moment of post cutting has no effect on the bond strength of fiber posts fixed with self-adhesive cement to the root canal. Key words:Fiber post, self-adhesive resin cement, push-out bond strength, operative dentistry.