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The influence of interfacial surface roughness on bilayered ceramic specimen performance
Garry J P Fleming1, Sherin F A El-Lakwah, Jonathan J Harris
1Biomaterials Unit, School of Dentistry, University of Birmingham, St Chad's Queensway, B4 6NN Birmingham, UK. g.j.flemming@bham.ac.uk
Summary
Smoother interfacial surface roughness in bilayered dental ceramics enhances flexural strength and reliability. However, smoother interfaces increase delamination risk, though fractures occur within the weaker dentin layer.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Dental Ceramics
Background:
- Bilayered dental ceramics are widely used for aesthetic and functional restorations.
- Interfacial properties significantly influence the mechanical performance of composite materials.
Purpose of the Study:
- To evaluate the impact of interfacial surface roughness on the mechanical performance of bilayered ceramic composite specimens.
- To determine the relationship between surface roughness, flexural strength, and fracture reliability.
Main Methods:
- Standard aluminous core porcelain discs were prepared with controlled surface flaw distributions.
- Specimens were bilayered with dentin porcelain and subjected to bi-axial flexure testing (ball-on-ring).
- Flexural strength, standard deviation, and Weibull moduli were calculated for groups with varying interfacial roughness.
Main Results:
- Specimens with smoother interfacial roughness exhibited significantly higher mean bi-axial fracture strengths and reliability.
- Delamination occurred in specimens with the smoothest interfaces, but fractures initiated in the dentin layer for rougher interfaces.
- Rougher interfaces prevented crack propagation along the interface, directing fracture into the weaker dentin layer.
Conclusions:
- Smoother interfacial surface roughness improves the strength and reliability of bilayered dental ceramic composites.
- Reduced interfacial tortuosity in smoother interfaces increases delamination susceptibility.
- Fracture behavior is influenced by interfacial roughness, with rougher interfaces promoting intra-layer fracture over interfacial delamination.