What are teeth crowns?
There are two types of teeth crowns ; metal crowns and metal-free crowns. Metals used in production of metal-ceramic teeth crowns are chrome, molybdenum or palladium, while before it was used nickel, but it was put out from use because of often allergic reactions. Metal crown has a tricky name, in fact only core of the crown is made of metal, while outer part is made of ceramic. Metal-free crowns are made from zirconium, to be exact zirconium-dioxide (ZrO2), which belongs in group of ceramic materials of very high firmness. We speak about oxide which, except for artificial teeth, is also used for artificial diamonds and other applications which demands high durability, in such way zirconium crowns are much durable than metal-ceramic ones. Behind zirconium, we also have lithium-disilicate crowns. They are made of full ceramic and should be used in single crowns and smaller teeth bridges in frontal regions of jaws, but for most patients the best result is achieved with zirconium crowns. There is also possibility to make teeth crowns from other materials like alloy of gold and titanium, but they are not so often because of its very big price.
Advantages of zirconium crowns
Even if metal-ceramic crowns are still represented in everyday dental practice, metal-free crowns made revolution in stomatology. As they appeared on dental market, metal-free ceramic crowns gave possibility to achieve same aesthetic level as natural shaped teeth. Unlike of metal-ceramic crowns, artificial teeth with ceramic crowns don’t refract light on unusual way and are not different than natural teeth. Reason for this undesired occurrence at metal-ceramic crowns is their gray metal core and thus the ceramic crowns made more popular lately. Fact that metal-free crowns don’t contain gray colour in background enables achieving very high aesthetic results with bright colours if patient demands very bright teeth. Zirconium is painted in any desired colour, for example, if the chosen colour of future ceramic-porcelain covers is A1, then zirconium is also painted in A1.
Other advantages
Other important advantages of metal-free ceramic crowns despite of metal-ceramic crowns is complete biocompatibility and preserving of teeth substance. Comparing with metal, which can cause alergic reactions, gums colour change, receiding gums, metal-free zircon crown is characterized with total absence of reaction of soft tissue and alergic reactions. At metal-ceramic crowns in neck area (connection between tooth and jaws) flaring can apear and thats why it’s recomended underlining with jaws, so the edge can be hidden behind.
When ceramic crowns are used, it’s not necessary to remove big amount of teeth substance what is case if we instal metal-ceramic crown. If we have to remove 1.5 to 2mm of tooth substance for metal-ceramic crown, for metal-free crowns we have to remove 0.5-1mm. Metal-ceramic crowns are still in use, mostly because of lower price when compared with metal-free. Patients sometimes choose combination of materials, so that in front regions of jaw they get metal-free crowns and metal-ceramic crowns in rear regions.
In some cases when patient has big lack of teeth but patient doesn’t want implants but dental bridge, it’s easier to override the gap with metal-ceramic dental bridge, because metal has better elastic performance compairing with ceramic metal-free crowns.