Selection of materials has essentially changed in dentistry due to technical improvements, such as composite fillings which have replaced mercury amalgam fillings. This tendency to abandon the use of metal in the mouth continues. Most probably, the jacket-crown (metal ceramic crown) will soon be history.

Attempts to avoid metal fused ceramic crowns are not new. All-ceramic crowns have been in use for a while now, especially in the front teeth area. The problem is that complicated bite situations, multi- unit bridges or molar crowns are contraindications for a lack of solidness.

The solution was found in zirconia oxide, a high-tech mineral ceramic having been in use in the field of orthopedics since 1969 for false hip joints.

As rigid and bio-tolerable as titanium, it lends itself perfectly for use in dentistry.
Procedure: After preparing the corresponding teeth and impression-taking, the model of the teeth situation is laser-scanned and transmitted to a high-tech milling machine, where the crown or bridge structure is designed by a CAD/CAM system. The obtained result is a precise, rigid and dimensionally stable structure.

On the contrary, metal structures (for metal ceramic crowns) are affected by the wear of time by deformed and frequently by oxidized crown margins. As a result, dark crown margins are frequent and lead to the accumulation of bacteria in the area of the deformed and unfitting margins and consequently to gum recessions.

However, zirconia crowns, being bio-attractive, do induce tissue adhesion.

The appearance of zirconia is extremely close to natural teeth for several reasons:

  1. Unlike those made of metal, the lightweight structure of zirconia crowns makes them feel like a natural part of the mouth
  2. Unlike metal which is conductive and may cause an unpleasant sensation towards hot and cold meals or beverages, zirconia crowns ensure that your teeth are not oversensitive to changes in temperatures
  3. Zirconia is naturally translucent to light, making crowns look natural

In order to take full advantage of the properties of zirconia, the choice of the right material is essential, given that a lot of brands launch some kind of zirconia on the market.

We opted for the market leaders Lava™ (3 M Espe – Seefeld/ Germany) being a zirconia with perfect esthetics as the material comes in different shades, scientifically profen superior accuracy of fit and unequalled load bearing capacities above 1200 Mpa. Due to its rigidity and strength there is no need for thick crown or bridge structures and thus it is possible to be much more conservative when preparing a tooth.

This zirconia is ideal for reconstructions of the posterior area and for multi-unit reconstructions due to the favourable friction encountered as a consequence of the fabrication procedure. This zirconia is worked in a pre-sintered status and then submitted to a heat of 1350º C causing a shrinkage of 30%. This shrinkage is accurately pre-calculated and implemented in the CAD/CAM design of the ceramic structure.

In the front teeth area Lava™ is esthetically impressive as the zirconia copings come in all 8 basic shades of the teeth-colour-guide making it possible to imitate even difficult combinations of colours.