Prosthetics of teeth in modern dentistry occupies a special and extremely important place. After all, no one is immune from their damage and subsequent loss. Today, the dental industry offers a huge variety of options for prosthetics. The preparation of teeth for metal ceramics, which is not in vain one of the most popular options, has some differences from processing for other types of crowns. The fact is that this method of prosthodontics organically combines an excellent aesthetic result, reliability, durability and relative cheapness.
The special metal frame, which forms the basis of such crowns and takes on the main load during the operation of the teeth, is complemented by a ceramic material that mainly performs an aesthetic function. So nature decreed that, perhaps,The most fragile and subject to rapid wear in our body are teeth. Considered to be the most reliable and durable prosthetic technology available today, metal-ceramics can successfully correct this state of affairs.
Dental prosthetics in general, and metal-ceramic crowns in particular, involve some initial preparation called preparation. After all, the oral cavity must be carefully prepared for such a procedure. The preparation of teeth for metal ceramics has a number of characteristic features that are associated with some additional requirements for this method of prosthetics.
According to modern standards of dentistry, the minimum possible thickness of the metal frame should be 0.3 mm, and the ceramic layer should be at least 0.8 mm. With a simple arithmetic operation, you can easily determine the thickness of a high-quality, durable crown, which is at least 1.1 mm. The preparation of teeth for metal-ceramic is designed to provide the necessary parameters.
Another goal pursued by such a preparatory procedure is to give the walls of the tooth a strict parallelism necessary for reliable adhesion to the crown (allowable inclination is only 7%). Otherwise, she may simply not hope. But the main point that distinguishes the preparation of teeth for metal ceramics is the need to create a special cervical ledge.
This unpleasant procedure is performed using local anesthesia. A qualified doctor treats teeth for metal ceramics as sparingly as possible. With the help of a turbine bur (average rotation speed - 250,000 rpm), equipped with a diamond tip, the dentist grinds hard dental tissues. To process proximal surfaces, a special separation disc or turbine tip is used, the diamond head of which has a smaller diameter than the ledge it creates.
For chewing surfaces, it is fundamentally important to maintain their anatomical shape. A preliminary ledge, both on the palatal surface and on the vestibular one, is created below the gum edge by about half a millimeter. After that, the proximal ledges are connected to each other, and the hard dental tissues are shaped into a truncated cone by additional grinding. Then sharp corners are rounded, and on this the process of forming a ledge can be considered completed. The main task of the dentist at the preparation stage is to prevent overheating of the tooth. Otherwise, the nerve will die. For this purpose, a water-air cooling system is used.
And finally, an interesting fact. Dental prosthetics was invented by the Etruscans, who lived on the territory of the modern Apennine Peninsula three thousand years ago. And porcelain dentures appeared in the eighteenth century. True, modern dental technologies, unlike methods of 300 years ago, allow almost anyone to make happy with the white-toothed smile of a Hollywood star.
