axial or isostatic pressing?

Pressing is one of the basic parameters which influences the final quality of the product, since it determines density, an extremely important aspect for clinical behaviour.
In order to ensure the product has sufficient cohesion for processing requirements, the ceramic granulate is loaded into a mould and pressed. Forming may use different technologies, depending on the geometrical complexity and dimensions of the product to be obtained and also its final application: 


Resistance to wear and mechanical resistance depend on the type of pressing used.

Isostatic pressing determines technical vaues 15% superior to those achieved with mono bi-axial pressing.

In order to obtain a blank of zirconia of highly-resistant and homogenous contraction of the product in all directions during the sintering phase, pressing must give the product homogenous density and porosity. Choice between axial or isostatic pressing therefore depends on the physical characteristics and geometries of each semi-processed product.

In contrast with axial pressing, isostatic pressing allows the pressure to be applied uniformly in all directions. The result is a “green product” (the name given to the pressed and not sintered product) characterised by a higher and more uniform density, which gives the sintered product excellent properties to the fired product, with mechanical and resistance values up to 15% higher than those of an axially pressed product.In fact, the lower internal porosity gives higher resistance to acids and therefore to the chemical agents present in the mouth, and also greater stability which delays deterioration and therefore aging during use. 

Less inner porosity gives a higher resistance to acids and to chemical agents in the oral cavity, as well as a higher cohesion which delays wear and aging in operation. 

Isostatic pressing technology is therefore undoubtedly preferable, due to its quality and technical characteristics, when complex work such as extended bridges and crowns with average/complex geometries are involved.