Luting Fiber Posts: Experimental Self-adhesive Resin Cement vs. Commercial Cements

Objectives: To evaluate micro push-out bond strength (BS) to radicular dentin and interfacial nanoleakage (IN) of an experimental dual-cure cement compared to commercially available dual-cure materials for fiber post cementation with or without light curing.
Methods: Root canal treatment was performed on 100 extracted monoradicular human premolars. Standardized 8mm post space was prepared for luting fiber posts (RelyX FiberPost, 3M ESPE), and the teeth were randomly assigned to five groups (N=20) according to the adhesive treatment: EXP - experimental resin cement (3M ESPE); LCD - LuxaCore Z Dual (DMG); MEC - Maxcem Elite Chroma (Kerr); CU - Calibra Universal (Dentsply); MA - Multilink Automix (Ivoclar Vivadent). Each group was further divided into two subgroups according to the polymerization protocol: light curing for 60s or dark curing for 2h. Additional 6 teeth per group were used for IN analysis. Root slices were prepared for micro push-out test and IN evaluation, after 24h (T₀) and 1-year storage (T₁₂) in artificial saliva. Results were statistically analyzed with three-way ANOVA or Chi Square test. Statistical significance was set at α=0.05.
Results: At T₀ no statistically significant differences in BS regarding the curing mode were observed among the groups. However, adhesive treatment had a significant influence (p<0.05) on BS, with EXP group showing highest BS values. At T₁₂ both adhesive treatment and curing mode was found to influence BS. EXP group presented with BS values comparable to LCD group, but superior to the other groups. At T₁₂, light cured groups, independently of the adhesive treatment, performed better than non-light cured groups. EXP group performed better regarding marginal infiltration when compared to other cements at T₁₂.
Conclusions: Light curing protocol in combination with the novel self-adhesive resin cement showed most promising results in terms of long-term push-out bond strength and IN when luting fiber posts.