Influence of a new light-curing system with optical fiber on the cementation of 3D-printed intraradicular posts

Objective: To evaluate the bond strength between root dentin and composite resin associated with a 3D-printed intraradicular post customized with flowable resin, using a fiber optic light-curing system that photoactivates the resin from within the post. Material and Methods: Thirty bovine teeth were used and divided into three groups (n=10): PHOTO (P) conventionally light-cured post (control); FIBER (F) post light-cured with optical fiber; FIBER+PHOTO (F+P) post light-cured with both optical fiber and conventional curing. The internal channel of the printed post allowed insertion of the optical fiber along the entire post length, enabling light transmission throughout the root canal. Bond strength was assessed using the push-out test, in which a load of 50 kgf was applied at a crosshead speed of 0.5 mm/min using a universal testing machine (EMIC, São José dos Campos, Brazil) for the cervical, middle, and apical thirds. Data were analyzed using two-way ANOVA and Tukey’s post hoc test (α=0.05). Results: There was a statistically significant difference between the root thirds, with higher bond strength values in the cervical third (4.224 ± 1.53 MPa), followed by the middle third (3.475 ± 1.32 MPa), and lower values in the apical third (1.768 ± 1.25 MPa). Furthermore, differences were observed in the distribution of failure types between the groups and the thirds evaluated. Conclusion: The root third significantly influenced bond strength, with higher values in the cervical region and lower values in the apical region. The light-curing system did not significantly affect bond strength; however, differences in failure patterns were observed among groups.