Comparison of the push-out strength of two fiber post systems dependent on different types of resin cements.

The purpose of this study was to compare the push-out strength of glass fiber posts dependent on the resin cement. One hundred human teeth were divided into five groups (n = 20). Two glass fiber post systems (DT Light SL (DTSL) and RelyX Fiber Post (RF)) were used. DTSL posts were cemented with one "etch & rinse" system (ER) or one of three self-adhesive resin cements (SA). The RF posts were cemented with RelyX Unicem. Afterwards, half of the specimens were thermocycled (TC; 5°C/55°C, 5,000 cycles). All specimens were cut into disks (thickness, 2 mm). The push-out test was performed (crosshead speed, 1 mm/min), fracture types were determined (×25 and ×40 magnification), and statistical analysis was performed (one-way analysis of variance (ANOVA), Scheffe test, p < 0.05). One-way ANOVA showed a significant influence of the resin cement on the push-out strength of the glass fiber posts before thermocycling (p < 0.001). After TC, no significant differences were detected. Microscopic evaluation showed mainly adhesive failures between post and cement for ER or mixed fractures for SA. The bond strength of adhesively cemented glass fiber posts is not dependent on the type of resin cement after TC. The use of SA can lead to bond strength values comparable to ER. Self-adhesive resin cements could be used just as well as resin cements with "etch & rinse" adhesive systems for the cementation of glass fiber posts.