Post-retentive ability of new flowable resin composites

To investigate the applicability of flowable composites as post luting agents by assessing the push-out strength of posts.

36 intact single rooted human premolars were selected. The endodontic treatment was performed and half of the specimens were restored with light transmitting posts (DT Light Post Illusion) and the other half with opaque posts (Tech 21 X-OP). In both groups the following combinations of adhesive/cement were tested: OptiBond Solo Plus/Nexus Third Generation (NX3), XP Bond/SureFil SDR Flow (SDR), and Vertise Flow (VF). Push-out test was used to assess the retentive strength of fiber posts, which was expressed in megapascals (MPa). Specimens were analyzed under a stereomicroscope to determine failure mode (adhesive between luting agent and post, adhesive between luting agent and dentin or mixed failure). Push-out data and failure mode distribution were analyzed by two-way ANOVA and Chi-square test, respectively (P< 0.05).

The statistical analysis revealed that only the type of luting material significantly influenced push-out bond strength of the post (P< 0.001). SDR (9.00 +/- 2.17 MPa) performed similarly to the control group NX3 (7.15 +/- 1.74 MPa), while VF (4.81 +/- 1.51 MPa) should significantly lower bond strength. Failure modes differed significantly among groups.