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Updated: Jul 12, 2026
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Quasistatic Mechanical Testing for Computer-Aided Design and Manufacturing Occlusal Veneers Cemented to Milled Dentin Analog Material
Published on: December 20, 2024
Strength influencing variables on CAD/CAM zirconia frameworks
Hang Wang1, Moustafa N Aboushelib, Albert J Feilzer
1Department of Dental Materials Science, Academic Center for Dentistry Amsterdam (ACTA), Louwesweg 1, 1066 EA Amsterdam, The Netherlands.
Summary
CAD/CAM milling damages zirconia, reducing its flexure strength. Surface treatments further weaken zirconia, leading to potential failures. Consider milling effects on zirconia frameworks for dental restorations.
Area of Science:
- Dental Materials Science
- Biomaterials Engineering
- Mechanical Engineering
Background:
- Zirconia is widely used in dental prosthetics due to its strength and biocompatibility.
- Surface treatments are common in dental laboratories to modify material properties.
- Previous studies often used polished zirconia as a control, neglecting in-situ surface conditions.
Purpose of the Study:
- To evaluate the impact of various surface treatments on zirconia's flexure strength.
- To specifically assess the effect of CAD/CAM milling on zirconia framework strength.
- To correlate surface damage with changes in flexure strength.
Main Methods:
- Prepared zirconia bars using both cutting/polishing and CAD/CAM milling.
- Applied surface treatments including air-borne particle abrasion (50 and 120 µm Al2O3) and heat treatment.
- Measured surface roughness and performed three-point bending tests.
- Analyzed fracture surfaces using scanning electron microscopy (SEM).
Main Results:
- Significant differences in flexure strength were observed across treatment groups.
- CAD/CAM milled zirconia showed reduced strength compared to polished controls.
- Particle abrasion with 120 µm Al2O3 resulted in the weakest zirconia specimens.
- A strong correlation (R²=0.912) was found between surface roughness and flexure strength.
- SEM revealed distinct surface and subsurface damage patterns.
Conclusions:
- CAD/CAM milling significantly compromises zirconia's inherent flexure strength.
- Subsequent surface treatments can further degrade zirconia's mechanical properties.
- Unexpected failures may occur due to combined milling and treatment effects.
- The characteristic strength reduction from CAD/CAM must be considered in dental restoration design.
