Dentistry >>>> Zirconium or ceramics - which is better?

Zirconium or ceramics - which is better?

A trip to a dental clinic for prosthetics usually begins with the patient's ignorance and ends with it. Not having enough detailed information about the forthcoming prosthetics, a person cannot make the right choice of the desired denture, which means that he misses the opportunity to assess the advantages and disadvantages of all the possibilities for improving teeth at his disposal.

Very common today designs of dental prostheses made of ceramics and zirconium dioxide (in everyday life - "zircon", "zirconium") have several varieties that determine the technology of their manufacture, for this reason it is always useful to figure out what advantages and disadvantages lie behind the beautiful names "zirconium prostheses "And" ceramic prostheses ". Zirconium or ceramics - which is better?

Ceramic prostheses were invented before zirconium only for the reason that people learned to work with glass, not yet having an idea of all the possibilities of representatives of a number of metals in the periodic table (zirconium dioxide is just an oxide of zirconium metal).

The basis of the ceramic (or porcelain) mass is silicon dioxide (non-metal silicon oxide) - a substance with high mechanical strength, but rather fragile upon impact, not withstanding temperature extremes. The advantage of ceramics (porcelain) is its inertness and electrical conductivity, which is very important for acidic environments, which is what saliva in the oral cavity is.

Ceramic prostheses can be either monolithic or combined. Monolithic ceramic prostheses - single porcelain crowns. Such crowns are suitable only in cases of destruction of the crown part (visible part) of the tooth without an adjacent defect (without the absence of adjacent teeth). Single porcelain crowns can restore the appearance of several teeth (and even the entire dentition), but each of these crowns will be an independent structure in the oral cavity. The advantage of this design is its solidity and chemical inertness (suitable for people with allergies to metals).

For the possibility of restoration of defects in the dentition (replacement of missing teeth), combined, metal-ceramic prostheses were invented, where the metal part is a supporting structure for the ceramic mass. Precious metals (platinum, gold), semi-precious metals (silver and palladium alloys) and stainless alloys (nickel, chromium, cobalt, titanium) can be used as a metal for the framework of a cermet prosthesis.

Combining the ceramic mass and the metal frame allows the property of silicon dioxide to enter into strong chemical bonds with metals at temperatures exceeding 1000 degrees.

Metal-ceramic dentures are not suitable for people who are allergic to metals, and not in all cases they can be attributed to chemically inert materials, since some non-precious alloys are capable of provoking electrolytic reactions with high acidity of saliva.

Metal-ceramic prostheses (including single metal-ceramic crowns) are in no way inferior to porcelain crowns in aesthetic qualities, but unlike porcelain crowns, they are not monolithic structures, which sometimes leads to chips of ceramic mass from the metal frame. One of the disadvantages of a metal-ceramic prosthesis is its weight (especially when it comes to gold frames and stainless alloys, or about fitting the prosthesis on implants). Ceramic mass is a rather heavy material, together with the weight of the metal frame creates a substantial load on the supports. The severity of the denture is important, as it creates an additional load on the periodontium (the tissues surrounding the tooth), can lead to periodontal inflammation, and to loosening of the abutment teeth.

Zirconia prostheses are as diverse as ceramic constructions. The property of zirconium dioxide, as a superhard material, makes it possible to make from it not only single crowns, but also small bridges (to replace dentition defects). For the manufacture of a zirconium dioxide bridge, a prerequisite is a small gap between the abutment teeth (no more than two missing chewing teeth and no more than four missing teeth in a row in the frontal part of the dentition). For comparison: when prosthetics with metal-ceramic structures, only four supports for the bridge are enough (only four teeth (or implants) located around the perimeter of the jaw to make a single bridge for 12-14 teeth).

Zirconium dioxide for use in dental orthopedics is a light-colored monolithic workpiece, from which a milling machine, under the guidance of a computer program, grinds a finished prosthesis (at the same time the entire structure with a selected number of crowns and missing teeth). For comparison: ceramic prostheses are made by hand by layer-by-layer application of a ceramic mass and layer-by-layer firing. The manufacture of ceramic prostheses (including combined ones) is considered a labor-intensive process, since it is done manually, zirconium prostheses require high-tech technological equipment for the manufacture, since the main part of the work is performed by an automated mechanism under the control of a computer.

Zirconium dioxide is a translucent material, which makes it possible to simulate the same effect as real teeth. But the color palette of zirconium blanks is poor, and if the natural color of zirconium dioxide does not match the natural color of the existing teeth, then it is changed by applying a colored ceramic coating. Thus, an all-zirconium prosthesis turns into a kind of combined zirconium-ceramic prosthesis, the basis of which is zirconium dioxide (metal oxide), and the lining is silicon dioxide (non-metal oxide).

Concerns about the reliability of the connection of a zirconium dioxide prosthesis with a ceramic veneer will help to dispel the fact that zirconium dioxide forms strong chemical compounds with silicon dioxide at high temperatures and, to some extent, itself turns into glass during firing.

Zirconium prostheses are much lighter than metal-ceramic (they do not load either teeth or implants), they can be made monolithically for a certain number of teeth (as opposed to all-porcelain), are more precise in manufacturing, do not heat up (are not thermally conductive), but can cause an allergic reaction to metal, since they are still made of metal oxide.

When making a choice between zirconium and ceramic prostheses, it is necessary to correlate not only the prices of their manufacture, but also the state of health of the body in general, and in particular the health of the abutment teeth, so that financial investments do not turn out to be a waste.