Dental prosthetics in modern dentistry occupies a special and extremely important place. Indeed, no one is immune from their damage and subsequent loss. Today, the dental industry offers a huge variety of prosthetics options. Preparation of teeth for cermet, 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 prosthetics organically combines an excellent aesthetic result, reliability, durability and relative cheapness.
A special metal frame, which forms the basis of such crowns and assumes the main load during the operation of the teeth, is complemented by a ceramic material that performs mainly aesthetic function. So nature ordered that perhaps the most fragile and susceptible to rapid wear in our body are teeth. Cermet, which is considered the most reliable and durable prosthetics technology to date, can successfully correct this state of affairs.
Dental prosthetics, in general, and prosthetics with ceramic-metal crowns, in particular, presuppose some initial preparation, called preparation. After all, the oral cavity must be carefully prepared for such a procedure. Preparation of teeth for cermet has a number of characteristic features that are associated with some additional requirements for this method of prosthetics.
By 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. Using simple arithmetic, you can easily determine the thickness of a high-quality, durable crown, which is at least 1.1 mm. Preparation of teeth for cermet is intended to provide the necessary parameters.
Another goal pursued by such a preparatory procedure is to give the tooth walls the strict parallelism necessary for reliable adhesion to the crown (allowable slope is only 7%). Otherwise, she may simply not wear it. But the main point that distinguishes the preparation of teeth for cermet is the need to create a special cervical ledge.
This unpleasant procedure is performed using local anesthesia. A qualified doctor treats teeth under metal ceramics as gently as possible. Using a turbine bur (average rotation speed of 250,000 rpm) equipped with a diamond tip, the dentist grinds hard dental tissue. To process the approximate surfaces, a special separation disk or turbine tip is used, the diamond head of which has a smaller diameter than the ledge created by it.
For chewing surfaces, it is crucial to preserve their anatomical shape. A preliminary ledge, both on the palatine surface and on the vestibular, is created below the gingival margin by about half a millimeter. After that, the approximate ledges are interconnected, and hard dental tissues are additionally turned into a truncated cone. 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 stage of preparation is to prevent overheating of the tooth. Otherwise, the nerve will die. For this purpose, a water-air cooling system is used.
And in conclusion, 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 technology, unlike the methods of 300 years ago, allows almost anyone who wants to make Hollywood stars smile with a white-toothed smile.