Flexural Strength
Flexural strength is a term frequently used in the dental lab world.
Flexural strength is a term frequently used in the dental lab world.
Flexural strength is a term frequently used in the dental lab world. It is expressed in the metric system as megapascals or MPa. Megapascal is the mega unit used to measure the intensity of pressure or force per unit area that a material is able to withstand before breaking. Every manufacturer of dental materials provides MPa values that indicate flexural strength. With good reason: flexural strength is a key value when it comes to the durability of a material such as zirconium oxide.
From a scientific point of view, flexural strength is the resistance of a material to breakage or fracture. Flexural strength indicates how much force is required to break a test sample of a defined measurement diameter.
As soon as this value is exceeded, the test specimen breaks. The higher the value, the more impacting forces the material can withstand. However, the flexural strength determined during a test depends heavily on the measuring method used and the surface preparation of the test samples, for instance on whether a material is polished or ground.
Comparisons between different materials are therefore not always definitive and values measured with different measuring methods are not comparable. For the values to be comparable, they must be obtained using the same measuring method. Current research is pushing towards an industry standard, but that has not been currently achieved.
Materials with high flexural strength offer advantages with these applications in particular:
Zirconia is probably the best-performing all-ceramic material in dentistry in terms of flexural strength. Lower translucency dental zirconias have a flexural strength of approximately 1,200 MPa. Among the translucent zirconia materials, flexural strength ranges from 600 to 900 MPa. The relationship between strength and translucency in the oxide ceramic material currently available is inversely proportionate.
The higher the translucency of a material, the lower the flexural strength and the higher the flexural strength of a material, the lower its translucency.