Expert interview: VITA SUPRINITY composition and develoment

As project partners of VITA Zahnfabrik and DeguDent, Dr Jörn Probst and Dr Bernhard Durschang from the Fraunhofer Institute for Silicate Research (ISC) in Würzburg, Germany have played an active role in recent years in encouraging the development of new zirconia-reinforced, lithium-silicate glass ceramic (ZLS). Here they report on the composition, structure and properties of these materials.

The building blocks for success

Dr Probst and Dr Durschang explain that "Unlike previous commercially available glass ceramics, zirconia-reinforced lithium-silicate glass ceramic (ZLS) contains an increased proportion of glass and zirconia (approx. 10 Wt% ZrO2). Moreover, all the crystalline components are relatively small (approx. 0.5 μm) so that only a limited amount of light refraction is possible. The result is that zirconia-reinforced, lithium-silicate glass ceramic (ZLS) has a high level of translucency without any shade of its own".

Making the difference

In tests, zirconia-reinforced lithium-silicate glass ceramic (ZLS) demonstrates biaxial strength that is approx. 70 MPa* higher than that of lithium-disilicate glass ceramic and offers superior processing characteristics as well as the possibility of directly verifying the material for visible faults. This is true both in the case of machine-based CAM processing (before and after crystallisation) as well as in manual reworking and polishing.

Positive future outlook

Dr Probst and Dr Durschang are certain: "Further improvements to the material system and in fabrication techniques are making levels of flexural strength in the range of 500 MPa seem like an achievable possibility."

1. Data on File.