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Flexure tests on dental ceramics
1Department of Mateials Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
The International Journal of Prosthodontics
|September 1, 1996
Summary
Different flexural testing methods yield varying failure stress results for dental ceramics. Procera AllCeram demonstrated superior strength across all tests, highlighting the importance of standardized testing protocols for accurate material comparison.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Dental Ceramics
Background:
- Accurate assessment of dental ceramic strength is crucial for clinical success.
- Various flexural testing methods exist, but direct comparison of results can be challenging due to differing stress distributions.
- High-purity alumina (Procera AllCeram), glass-infiltrated alumina (In-Ceram), and leucite-reinforced porcelain (IPS Empress) are common dental materials.
Purpose of the Study:
- To evaluate the failure stresses of Procera AllCeram using three distinct flexural testing methods: three-point bend, ring-on-ring, and piston-on-three-ball.
- To compare the failure stresses of In-Ceram and IPS Empress with Procera AllCeram using ring-on-ring and piston-on-three-ball tests.
- To investigate a method for comparing failure stress data obtained from different testing configurations.
Main Methods:
- Flexural strength testing of Procera AllCeram, In-Ceram, and IPS Empress using three-point bend, ring-on-ring, and piston-on-three-ball configurations.
- Calculation of failure stresses for each material under each test condition.
- Application of Weibull analysis to the failure stress data.
- Consideration of the effective specimen area under maximum tensile stress for data comparison.
Main Results:
- Failure stresses varied significantly (up to 50%) among the different testing methods for all materials, precluding direct comparison.
- Procera AllCeram consistently exhibited higher failure stress compared to In-Ceram and IPS Empress across the tested methods.
- Accounting for the effective specimen area under tensile stress enabled a more meaningful comparison of failure stress data.
Conclusions:
- The choice of flexural testing method critically influences the measured failure stress of dental ceramics.
- Procera AllCeram demonstrates superior flexural strength relative to In-Ceram and IPS Empress.
- Standardized testing protocols and appropriate data analysis methods, such as considering effective specimen area, are essential for reliable material characterization and comparison in dental applications.