Evaluation of Mechanical and Physical Properties of Implant- Supported Crowns Produced from Different 3D-Printed...

This study aimed to compare the mechanical and surface properties of hybrid ceramic materials fabricated using different techniques for fixed dental restorations and to evaluate the clinical relevance of digital manufacturing. Five permanent hybrid resin materials produced via 3D printing and one hybrid ceramic fabricated by milling were assessed in terms of fracture resistance, surface roughness, and microhardness.

Six groups were formed: five 3D-printed resins and one milled ceramic. For each group, 20 molar-shaped crowns were fabricated and divided into pre-aging and post-aging subgroups for fracture resistance testing. Additionally, 120 disk-shaped specimens were prepared. Crowns were cemented using resin cement under finger pressure and tested with universal testing machine. Surface roughness was measured with a profilometer, and microhardness was assessed using Vickers hardness tester. All specimens underwent thermal aging before retesting. Data were analyzed using SPSS.

Significant differences in fracture resistance were found among groups (p<0.05). Flexcera Smile Ultra+ showed the highest values. Aging reduced fracture resistance in all groups. Senertek P-Crown V3 and Vita Enamic had higher surface roughness initially, with only Senertek P-Crown V3 showing significant post-aging decrease. The milled ceramic group showed higher microhardness than all 3D-printed groups. Post-aging, hardness increased in all but the Vita Enamic group.

Material selection and fabrication technique should be based on clinical requirements. Milled ceramics provide superior mechanical strength. However, the surface roughness of 3D-printed materials remained above the clinically acceptable threshold of 0.2 µm.