From metal-ceramics to all-ceramics

Significant shortcomings of resin as covering materialThe introduction of metal-ceramics more than 40 years ago resulted in significant progress at fabrication of prosthetic restorations in the tooth colour. The shortcomings of the restorations with resin as covering material (e.g. insufficient resistance against colouring and insufficient strength) were eliminated by the use of the dental ceramics as covering material.
Progress due to metal-ceramicsThe introduction of metal-ceramics more than 40 years ago resulted in significant progress at fabrication of prosthetic restorations in the tooth colour. The shortcomings of the restorations with resin as covering material (e.g. insufficient resistance against colouring and insufficient strength) were eliminated by the use of the dental ceramics as covering material.
Improved aesthetics in cervical area

The following materials and techniques are used for aesthetic optimization:

  • gold-coloured framework materials
  • modified framework forms
  • ceramic stair
Improved bondingThe risk of insufficient bonding between the metal framework and covering material may be considered nowadays - at least with materials from noble metals with high content of gold - to be solved. Considering any and all possible reasons of failure, it is possible to determine the yearly failure share of 1-1.5% with metal-ceramic restorations.
 On the basis of the long-term clinical use the metal-ceramics are considered to be safe and clinically tested procedure. Thus it is a comparative standard for new procedures of restoration fabrication in dental prosthetics. However, the limit factor of aesthetic success with metal-ceramic restorations includes the missing light permeability of the metal framework. Furthermore there exists a risk of material incompatibility with alloys free of noble metal content (e.g. nickel, cobalt, chrome).
More aesthetics from all-ceramics In comparison with the information above, all-ceramic restorations can offer higher aesthetic potential due to their improved translucency and transparency. Excellent biocompatibility and low affinity toward plaque predetermines them to be an ideal material for restorations.
Limit: constant strengthThe insufficient steady strength has been limiting the use of all-ceramic restorations for a long time on the market of common dental ceramics. The application of clean covering ceramics for the fabrication of all-ceramic restorations may be recommended only for small indication spectrum, e.g. inlays or facets.
The enhanced strength increases the clinical safety of success
For the fabrication of the whole crowns there are necessary ceramic systems with the enhanced mechanical properties otherwise the early clinical failure can be anticipated.
The significant strength enhancement in comparison with Feldspat covering ceramics was achieved by the use of glass-ceramics reinforced by leucite (e.g. CERGO, Degussa Dental/Hanau; Finesse, Dentsply DeTrey/Konstanz) which are mostly heat and pressure processed and according to the Lost - Wax principle.
Single restorations bonded by adhesive

All-ceramic restorations which are heat and pressure processed are suitable for the following indications:

  • inlays
  • facets
  • partial crowns
  • crowns

For the sufficient safety of clinical success bonding with adhesive is inevitable with these materials.



Clinically verified for single restorations bonded by adhesive After more than 10-year clinical application this procedure can be deemed as safe. After 5-year monitoring it provides the safety of success approximately comparable with the one observed with metal-ceramic restorations.
Extension of indications due to innovative all-ceramic materials

Further extension of indications for all-ceramic systems could be achieved only by the use of ceramics with higher values of constant strength such as e.g. carbon and zirconia oxides. Aluminium oxide has been used for dental ceramics reinforcement for already several decades. The use of porous frameworks penetrated by glass from aluminium oxide causes satisfactory success prognosis in case of single crowns and small bridges applications in the frontal part.

Along with the extension of indications there was enabled also common cementing with the use of all-ceramic restorations aluminium oxide based. The fabrication of bridges on the basis of this material in the lateral part does not ensure success with respect to the limited mechanical properties.


Issue of bridge frameworks in lateral partIt was impossible to fabricate all-ceramic bridge frameworks in the lateral part in such a manner so that it can ensure sufficient clinical prognosis of success despite the progress achieved during the last 20 years. The metal-ceramic frameworks have been the only material combination enabled for the bridges in the lateral part so far what provided sufficient clinical safety of success. The metal-ceramic bridge may be fabricated both with facets and with all-surface ceramic cover.
Zirconia oxide as material for frameworks of the futureIt was impossible to fabricate all-ceramic bridge frameworks in the lateral part in such a manner so that it can ensure sufficient clinical prognosis of success despite the progress achieved during the last 20 years. The metal-ceramic frameworks have been the only material combination enabled for the bridges in the lateral part so far what provided sufficient clinical safety of success. The metal-ceramic bridge may be fabricated both with facets and with all-surface ceramic cover.