The effect of different adhesive system applications on push-out bond strengths of glass fiber posts

Abstract

Purpose: Over the past years, the adhesion of fiber posts luted with simplified adhesive systems has been a matter of great interest. The aim of this study was to assess the post retentive potential of a self-adhesive resin cement using different adhesive systems to compare the push-out bond strengths of fiber posts.

Materials and methods: The post spaces of 56 mandibular premolar roots were prepared and divided into 4 experimental groups and further divided into 2 subgroups according to testing time (n=7). The fiber posts (Rely X Fiber Post) were luted with a self-adhesive resin cement (RelyX Unicem) and one of the following adhesive systems: no adhesive, a total-etch adhesive resin (Single Bond), a two-step self-etch adhesive resin (Clearfil SE Bond) and a one-step self-etch adhesive resin (Clearfil S3 Bond). Each root was cut horizontally, and 1.5 mm thick six root segments were prepared. Push-out tests were performed after one week or three months (0.5 mm/min). Statistical analysis were performed with three-way ANOVA (α=.05).

Results: Cervical root segments showed higher bond strength values than middle segments. Adhesive application increased the bond strength. For one week group, the total-etch adhesive resin Single Bond showed higher bond strength than the self-adhesive resin cement RelyX Unicem applied without adhesive resin at middle region. For 3 months group, the two-step self-etch adhesive resin Clearfil SE Bond showed the highest bond strength for both regions. Regarding the time considered, Clearfil SE Bond 3 months group showed higher bond strength values than one week group.

Conclusion: Using the adhesive resins in combination with the self-adhesive resin cement improves the bond strengths. The bond strength values of two-step self-etch adhesive resin Clearfil SE Bond improved as time passes.

Keywords: Adhesive resin; Bond strength; Fiber post; Push-out test; Resin cement.

Fig. 1

Photograph of the push-out test.

Fig. 2

The failure photographs of each group. (A) Adhesive in dentin, (B) Adhesive in post, (C) Mixed, (D) Cohesive.

Fig. 3

Predominating type of fracture occurred in each group (%). ^*U: RelyXUnicem without adhesive, SB: Single Bond, CSE: Clearfil SE Bond, CS3: Clearfil S3 Bond, (c): cervical root segment, (m): middle root segment.