Impact of a plant-derived agent on bond strength of self-adhesive resin cement luting of glass-fiber posts

This study aimed to evaluate the effectiveness of plant-derived compounds, lignin (LIG) and proanthocyanidin (PAC), either alone or in combination with EDTA, as pre-treatments for intraradicular dentin to enhance the push-out bond strength (PBS) of glass fiber posts (GFP) cemented with self-adhesive resin cement. Forty-two healthy human single-rooted premolars were prepared for GFP cementation and divided into the following groups based on the dentin pre-treatment: 1) Control: no pre-treatment; 2) EDTA: 17% EDTA; 3) LIG: 2% LIG; 4) PAC: 2% PAC; 5) EDTA-LIG: 17% EDTA + 2% LIG; and 6) EDTA-PAC: 17% EDTA + 2% PAC. All solutions were applied for 60 seconds. The GFPs were subsequently cemented using the self-adhesive resin cement RelyX U200. The roots (n = 7 per group) were sectioned into 1-mm thick discs and subjected to PBS testing after 1 week and 6 months. Statistical analysis was performed using two-way ANOVA followed by Tukey's test (p < 0.05). After one week, the Control and EDTA-LIG groups (p = 0.092) exhibited similar and high bond strength values compared to the EDTA, LIG, and EDTA-PAC, while the PAC showed the lowest PBS. After six months, the EDTA-LIG maintained its bond strength values (p < 0.001), with no significant differences from the other groups, except for the PAC. In conclusion, the intraradicular dentin pre-treatments exhibited behavior comparable to untreated RelyX U200 cement in the bonding between the fiberglass post and intraradicular dentin, except proanthocyanidin.