In the following article, we will examine the better choice of crowns - metal-ceramic or zirconium. At the very outset, however, it has to be mentioned that we will not focus on what the underlying basis for the prosthesis is - a treated tooth or a twisted implant- seeing as both types of crowns can successfully be used in either case.
Needless to say, we all understand that gold crowns are obsolete and rightly belong to the previous century. Modern aesthetic dentistry offers excellent opportunities to specialists, to whom it is vital to recreate a functional tooth that can be distinguished by its special aesthetics and naturalness. Indirect restoration helps in this, through the installation of metal-ceramic and zirconium crowns.
Metal-ceramic or Zirconium dental crowns
- Metal-ceramic dental crowns
Metal-ceramic dental crowns are the most commonly used crowns in the modern era. They have a frame that’s metallic and it is lined with ceramic. In comparison to plastic or metal crowns, ceramic crowns are much more durable and aesthetic. They also possess a “natural transparency”.
But just like the proverbial fly in the ointment, metal-ceramic crowns have their own disadvantages.
They are insignificant, but do need to be mentioned. Over time, the tooth under a metal-ceramic crown undergoes decay and so, the average lifespan of such procedures is about five years. And when the gum sags over time, the metal edge of the crown becomes visible, which doesn’t look very aesthetically pleasing, especially when a person smiles. But if the dentist and the technicians involved perform the installation correctly and ensure that all requisite care is taken, then the crown could last a very long time and offer immense satisfaction to the patient with its attractive and fresh look/appearance.
- Zirconium Dental Crowns
The most safe, aesthetic inconspicuous and expensive crowns are metal-free crowns. They are made from Zirconium dioxide or ceramics. In our subjective opinion, today, metal-free zirconium crowns are significantly ahead of metal-ceramic dental crowns across several parameters:
- Aesthetics (zirconia crowns do not look as aesthetically pleasing as ceramic crowns in terms of their refractive index, but can be a great budget alternative);
- Functionality (They withstand the heaviest chewing loads and so they can be safely installed on any teeth, regardless of their location in the mouth: front, lateral etc);
- Zirconia crowns are absolutely harmless and the stump does not deteriorate under such crowns (and even under zirconia crowns, the grinding of the teeth is much lesser than under metal-ceramic crowns).
Interesting to Know!
Zirconium dioxide is a state-of-the-art material that has been used in surgery for over 20 years. Use of this material in dentistry is a relatively recent practice. Since then, the porcelain crown has become less popular. Zirconia is distinguished by its exceptional bio-compatibility and it possesses the most optimal characteristics for the manufacture of dental prostheses. The composition of zirconium dioxide does not include metal , so it does not cause allergies. On the other hand, however, it has to be noted that the price of metal-free zirconia crowns is much higher.
Why are metal-free dental prosthetics better than metal-ceramics?
The main advantage of a metal-free zirconium crown is the absence of a black border along the gum edge, which could be visible when the gums recede from the crown (as they do, with metal-ceramic crowns). The second advantage is that due to its optical properties, i.e refraction and reflection of light, zirconium dioxide crowns are similar to natural dental tissue. This means that the prosthesis looks highly natural, in just about any lighting. Inside crowns for teeth of metal ceramic, there is a metal frame that does not allow light to pass through.
How are modern crowns manufactured?
There is a modern computer-based technology that makes it possible to create crowns, dental linings and veneers with the highest possible precision. This technology is called CAD/CAM. The process of manufacturing metal-free crowns is completely computerised. First, an exact 3D model of the tooth is developed on the monitor, following which the computer calculates the precise dimensions of the prosthesis and relays this data to a modern dental mill, on which the structure for the zirconium prosthetics is ground.
Using CAD/CAM technology to manufacture prostheses ensures that all possible inaccuracies are avoided. This ensures that the crowns fit snugly to the teeth and do not cause any discomfort to the patient.