There are several types of crowns in dentistry that are different from many points of view: the material used, the aesthetics obtained, the manufacturing process, the specialist’s indications.
The most famous crown is the metal – ceramic one, with the skeleton made of a non-noble metal alloy, cobalt chromium (Cr /Co). These have indications for the anterior and the lateral teeth or the implants.
The metallic skeleton is about 0,3- 0,5 mm thin, covered with a coat of opaque varnish to neutralize the colour of the metal, then the ceramics is layered according to the desired colour: enamel, dentine, effects.
The ceramics has a wide range of colours and a highly natural look can be achieved by combining various colours and pigments.
Ceramic crown on zirconia support
Zirconia, a white, tough and durable fabric is used to manufacture the cape and to obtain an aesthetics superior to those of the metallic and ceramic ones. The zirconium oxide is well tolerated, does not create allergies and does not corrode (as it is not a metal) , thus eliminating the possible occurrence of that grey contour of the gum due to the biological recession of the gum.
The thickness of the cape over which the ceramics is layered is about 0.5 mm. The works have an excellent precision and accuracy due to the technology used to manufacture crowns. The necessary system to process zirconium is CAD /CAM, a sophisticated technology that is not found in all dental laboratories, which explains the higher costs. Zirconia ceramic crowns have a look with translucent effects, which is very close to the natural teeth.
They are made entirely of ceramics, with no skeleton, and they are of two types: the EMAX pressed type and the Feld spathic type.
The pressed crown
By using this type of crown you can obtain an aesthetics superior to those that have a metallic frame or not. These are obtained from a lithium disilicate block which is milled through the CAD-CAM milling technique. The thickness of a ceramic crown is about 0.8 to 1.1 mm. This type of crown is mostly used in the frontal area, but it can also be used in the side, due to high resistance. The adhesive cementation techniques used contribute to the increased resistance.
The Feld spathic veneer
If a technician who masters the art of combining colours, pigments and textures is called for, this type of ceramic crown can lead to excellent results in terms of aesthetics. This should be coupled with an adequate training of the tooth within the cabinet. The tooth substance loss by grinding is minimal. The final effect is maximal in terms of naturalness and aesthetics.