Adhesion of Core Build-Up Materials to RelyX Fiber Post

Objectives: The aim of this in-vitro study was to evaluate the influence of different surface treatments of the new RelyX™ Fiber Post (RLXFP, 3M ESPE) on the adhesion of Filtek™ Z250 universal composite (Z250, 3M ESPE).

Materials and methods: The conical part of RLXFP (Size 3) was used. The surface was either left untreated or silanized with RelyX™ Ceramic Primer (RLXCP) or treated with Adper™ Prompt™ L-Pop™ (L-Pop) or Adper™ Scotchbond™ 1-XT (1-XT) or Adper™ Scotchbond™ Multipurpose (MP) or RLXCP & L-Pop or RLXCP & 1-XT or RLXCP & MP (all from 3M ESPE). Subsequently Z250 was added and light-cured (discs: d = 6,0 mm, h = 4,0 mm). All specimens were stored for one hour at 36 °C / > 95 % rel. humidity and for 23 hours in water at 36 °C, some were additionally thermocycled (5.000 cycles 5 °C / 55 °C). Finally a pull-off test was made using an universal testing-machine.

Results: The following table summarizes the adhesion values measured after 24 h or thermocycling (TC). Analysis of variances showed that coating (P = 0,000) and thermocycling (P = 0,036) had an significant effect on adhesion. Treatment of the post surface with the bonding agents resulted in increased bond strength compared to untreated, silanized or silanized and bonded surfaces.

Conclusions: There is no need to silanize the post, using the bonding agent of the core build-up material is advantageous.