The field of dental medicine is constantly evolving and advancing toward minimally invasive techniques. Several studies have demonstrated that bonding to the tooth structure, particularly enamel, yields the most predictable results. In some instances, however, significant tooth loss, pulpal necrosis, or irreversible pulpitis may limit the options available to the restorative dentist. In these cases, placement of a post and core followed by a crown is the preferred treatment option, provided all requirements are met. This literature review provides an overview of the historical development of dental FRC post systems as well as a comprehensive examination of the currently available posts and their bonding requirements. In addition, it offers valuable insights for dental professionals seeking to understand the current state of the field and the prospects of dental FRC post systems.
Background: The adoption of 3D printing in restorative dentistry is increasing, with the post-curing duration of a material being identified as a key determinant of its performance. This study evaluated the effect of the post-polymerization time on the flexural strength (FS) and Vickers microhardness (VHN) of a 3D-printed composite. Methods: Specimens of Formlabs Permanent Crown Resin were 3D printed and divided into four groups according to their post-curing time: no post-curing time and 20, 40, and 60 min post-curing time. Flexural strength testing was carried out using a three-point test of 40 bar-shaped specimens (n = 10/group), followed by fractography observations under a scanning electron microscope (SEM). Vicker microhardness testing was also conducted with 40 disk-shaped specimens (n = 10/group). The inorganic filler content was measured using the ash method, and the filler morphology was characterized under an SEM. Statistical analyses were performed using adjusted ANOVA and regression tests. Results: The highest median FS values were observed at 40 min post-curing (133.07 MPa), with significant differences across all groups (p < 0.0001). The highest median VHN values were found at 40 min post-curing (32.09 VHN), with significant differences between groups (p < 0.0001). A significant positive correlation (rho = 0.7488; p < 0.0001) was found between the flexural strength and Vickers hardness with changing post-curing durations. The 3D resin composite had an average filler content of 66.82% based on weight. Conclusions: With the limitation of the current in vitro setup, a post-polymerization time of 40 min was shown to lead to the best material performance. The post-printing polymerization time significantly affects the Vickers hardness and FS of 3D Formlabs Permanent Crown Resin. Further research should explore the effects of different resin compositions, clinical conditions, and curing protocols to enhance the general applicability of these findings. Clinical implications: Extending the post-printing polymerization time does not inherently result in improved material properties. A considered adjustment of the post-curing time can significantly impact the mechanical properties of a 3D-printed composite.
This study evaluated the effect of post-printing polymerization time on residual monomer elution and water sorption in a 3D-printed resin composite. Eighty samples were fabricated and assigned to four groups based on post-curing duration: 0, 20, 40, and 60 min. Each group was subdivided according to two storage conditions (distilled water and 75% ethanol–water solution), and evaluated at 1 and 7 days. High-performance liquid chromatography (HPLC) quantified eluted monomers. Additionally, 40 specimens underwent a 4-month sorption/desorption cycle for water sorption and solubility assessment. Data were statistically analyzed using kernel regression (monomer data) and Welch ANOVA (water sorption and solubility) at a significance level of p < 0.05. BisEMA was the only monomer detected, with significantly higher elution recorded in ethanol-based storage. Increasing post-curing time notably reduced both monomer release and water sorption/solubility (p < 0.001); however, the optimal results were observed at 40 min post-curing. These findings suggest that extending post-curing beyond an optimal threshold does not further improve composite properties, underscoring the importance of identifying precise curing parameters in order to enhance durability and material performance.