Shear bond strength of vat photopolymerization additive-manufactured zirconia to veneering ceramic.

Abstract

Purpose: To evaluate the shear bond strength (SBS) of stereolithography (SLA), digital light processing (DLP) manufactured, and computer numerical control (CNC) milled zirconia to veneering ceramic.

Materials and methods: Rectangular shaped zirconia substrates (10 × 5 × 5 mm³) were manufactured through SLA, DLP, and CNC technology separately. Their surface roughness was measured and the surface topography was analyzed by atomic force microscope (AFM). Then the veneering ceramic (5 × 5 × 5 mm³) was applied to carry out the SBS test. Failure modes were examined by a scanning electron microscope (SEM). The data of SBS and roughness were statistically analyzed with one-way ANOVA followed by S-N-K post hoc comparisons (a = 0.05).

Results: The surface roughness of the SLA group (0.38 ± 0.03 µm) and the DLP group (0.37 ± 0.04 µm) were both significantly higher than the CNC group (0.16 ± 0.00 µm) (p < 0.001). AFM results revealed irregular surface of SLA and DLP zirconia. No significant difference was found in SBS value of the three groups (p = 0.253). SEM image showed different failure modes including cohesive, adhesive, and mixed failure.

Conclusion: The bonding ability of SLA and DLP zirconia to veneering ceramic were comparable with that of CNC zirconia.