Clinical evaluation of 3D-printed zirconia crowns fabricated by selective laser melting (SLM) for posterior teeth restorations: Short-term pilot study.

Background/purpose: Zirconia crowns (ZrC) without veneering porcelain have become an effective alternative in clinical practice. Monolithic zirconia restorations fabricated by the dry milling method do not have acceptable clinical properties. This study evaluated the periodontal qualities of three-dimensional printed ZrC using the modified United States Public Health Service (USPHS) criteria. Materials and methods: A total of 15 patients who required dental crowns were recruited, and all 15 teeth were restored with digital 3D-printed ZrC. All crowns were assessed at the time of crown placement and 2, 6, and 24 weeks post-placement. Clinical parameters, including plaque index, gingival index, probing depth, crown marginal integrity, and attrition of the antagonist's teeth, were evaluated and recorded. Results: According to the Modified California Dental Association quality evaluation system, 100% of the crowns received satisfactory grades. Despite the significant increase in plaque index and gingival index at two weeks post-ZrC placement, there was no deterioration in probing depth. Moreover, there was discard usage of ZrC on the antagonist's teeth at 24 weeks posttreatment. Of the 15 crowns, one tooth had to be extracted due to a vertical root fracture. Overall, the digital 3D-printed crowns showed no adverse effects on periodontal tissues after 24 weeks of follow-up. Conclusion: The 3D-printed ZrC showed no periodontal problems. It can serve as an alternative for patients, particularly those with high esthetic expectations.

Synergistic Effect of Static Magnetic Fields and 3D-Printed Iron-Oxide-Nanoparticle-Containing Calcium Silicate/Poly-ε-Caprolactone Scaffolds for Bone Tissue Engineering.

In scaffold-regulated bone regeneration, most three-dimensional (3D)-printed scaffolds do not provide physical stimulation to stem cells. In this study, a magnetic scaffold was fabricated using fused deposition modeling with calcium silicate (CS), iron oxide nanoparticles (Fe3O4), and poly-ε-caprolactone (PCL) as the matrix for internal magnetic sources. A static magnetic field was used as an external magnetic source. It was observed that 5% Fe3O4 provided a favorable combination of compressive strength (9.6 ± 0.9 MPa) and degradation rate (21.6 ± 1.9% for four weeks). Furthermore, the Fe3O4-containing scaffold increased in vitro bioactivity and Wharton's jelly mesenchymal stem cells' (WJMSCs) adhesion. Moreover, it was shown that the Fe3O4-containing scaffold enhanced WJMSCs' proliferation, alkaline phosphatase activity, and the osteogenic-related proteins of the scaffold. Under the synergistic effect of the static magnetic field, the CS scaffold containing Fe3O4 can not only enhance cell activity but also stimulate the simultaneous secretion of collagen I and osteocalcin. Overall, our results demonstrated that Fe3O4-containing CS/PCL scaffolds could be fabricated three dimensionally and combined with a static magnetic field to affect cell behaviors, potentially increasing the likelihood of clinical applications for bone tissue engineering.