Mechanical Properties and Bond Strength of Additively Manufactured and Milled Dental Zirconia: A Pilot Study.

PURPOSE: To evaluate and compare the mechanical properties and ceramic bond of additively manufactured and milled dental zirconia materials.

MATERIALS AND METHODS: Disc (r = 10 mm, h = 2 mm) and bar (254) shaped milled (M group) (Nacera Pearl; Doceram) and additively manufactured (AM group) (NanoParticul Jetting; XJet, Carmel 1400) zirconia specimens were prepared for 2 experimental groups. Ceramic was applied to the disc specimens (h = 4 mm, r = 6 mm) (n =9) and their shear bond strength (SBS) was measured. The surface morphology of disc specimens was analyzed with a scanning electron microscope (SEM). The Vickers microhardness (Vh), surface roughness (Ra), and three-point flexural strength (FS) of bar specimens (n = 9) were measured. Results were statistically analyzed with Mann-Whitney U-test (α = 0.05) RESULTS: : Significant differences were found in FS and Vh values of the M and AM groups. M group (1501.4 ± 60.1 HV1) showed a significantly higher Vh value than the AM group (1169.2 ± 48.4 HV1) (p < 0.001). FS of the M group (1287.5 ± 115.2 MPa) exhibited significantly high value than the AM (1030.0 ± 29.2 MPa) group (p < 0.001). Statistically, no significant differences were seen in SBS and Ra values of the M and AM groups.

CONCLUSION: Within the limitations of this in vitro study, the manufacturing technique affected the mechanical properties of the zirconia materials. AM zirconia material showed lower Vh and FS values than M zirconia. Additionally AM zirconia demonstrated adequate bond strength with dental ceramic. This article is protected by copyright. All rights reserved.