Prettau Zirconia06.09.2015.

The zirconia for restorations without veneering

Prettau® Zirconia is the material of choice for frequently occurring problems like reduced available space, bruxism or ceramic chipping. It offers a functional and at the same time aesthetical solution.

This highly biocompatible and non-porous material distinguishes itself through its extremely high translucency and perfectly natural appearance. Due to these characteristics and if used in conjunction with a special colouring technique, the use of veneer ceramics can be entirely eliminated. In this way, aesthetically pleasing full-zirconia restorations, i.e. the Prettau® Bridge can be realized.
Range of applications

• Partial and single crowns
• Inlays, onlays and veneers
• Bridges with up to 14 elements (occlusally screwed or cemented)
• All indications can be manufactured fully anatomically or reduced for veneering with ceramics

Characteristics
Prettau® Zirconia is partially stabilized with yttrium and enriched with aluminium. This results in positive material properties like a high bending strength of up to 1,570 MPa (Study of the University of Munich, Dr. Beuer, February 2007), a high temperature resistance (of up to 2,600°C), as well as a constant shrinking factor granting the highest possible precision.
• Higher translucency due to optimized microstructure of the zirconia
• No ceramic chipping
• No abrasion to the antagonist tooth
• 200% higher bending strength, thanks to the elimination of the veneer ceramics
• Especially suited in case of implants, reduced available space or restorations with gingival reconstruction

Material composition
Zirconia is the result of a chemical process: the basis is zirconia sand, partially stabilized with yttrium and made into Zirconia blanks through a mechanical process. Among the dental ceramics available today, zirconium oxide is without any doubt the material with the highest flexural and tensile strength.

By omitting the ceramic layering, a more massive structure can be created, resulting in an overall higher resistance of over 200%. In this way, ceramic chipping and abrasion to the antagonist are being avoided.

Abrasion behaviour
Compared to polished zirconia, a tooth veneered with ceramics is 10,000 times more abrasive. The porous structure of the layered ceramic acts like sandpaper and causes wear on natural dentition.
This phenomenon can be illustrated using a practical example:
Rubbing our hands together creates abrasion, which can cause open skin areas. Rubbing our hands against a window pane makes the hand slip on the glass surface. This causes a minimal friction and heat, but no abrasion. Something similar is happening when sintered zirconia meets the natural tooth.
Zirconia in sintered state is perfectly smooth and non-porous, so that it slips on the natural tooth without friction, same as a hand on a window pane.

In general we can say:
The harder and smoother the material, the lower is the material wear caused by friction and hence also abrasion.