New era in dentistry and dental prosthetics began ten years ago. It seems that we can forget about the fillings under which tooth decay develops or about the crowns which last less than three months. Revolutionary news is called CAD/CAM. It is based on 3D computer programmes which are used for manufacturing of perfect dental replacements, crowns, bridges, facets, inlays, onlays. When applying traditional manufacturing procedures for dental restoration, it was impossible to avoid mistakes because the operational area was very narrow and not clearly visible. This technology enables you to work outside the tooth cavity. Complex computer software is correcting possible human mistakes.
CAD / CAM dentistry (computer guided design and computer supported manufacturing in dentistry) is the branch of dentistry which deals with manufacturing of various dental restoratio, including crowns, crown bases known as “core”, veneers, inlays, onlays, fixed bridges, restorations on dental implants by using CAD/CAM technology.
Background information
Although CAD / CAM system was used in dentistry in the middle of 1980s, early efforts were considered to be great innovation which consumed excesive amount of time for production of cost effective product. The cost-ineffectiveness prevented the use of this system in dental clinics and limited them to be used only in laboratories. However, use of CAD/CAM technology with improved software and advanced material has increased in dental clinics, as support in technical laboratories.
Difference from conventional restoration
CAD / CAM restoration in dental clinic differs from conventional way of manufacturing of dental restorations, because it enables manufacturing of dental restoration in one day. Patients who are waiting for their conventional dental restorations to be manufactured, for example, crowns, have temporary crowns which stay on their drilled tooth from one to several weeks, how long it takes for the dental laboratory to produce definite crown. Following the finalization of definite crown, temporary ones are being removed and definite crowns are fixed by cementing. CAD / CAM system in dental clinic enables dentist to manufacture inlay or any other type of dental restoration very quickly – in same cases it takes only one hour. CAD / CAM restoration are more conservative in terms of tooth preparation. Since the dental restoration joints better with the tooth enamel than with tooth dentin, drilling has to be done carefully not to eliminate the enamel layer from the tooth.
CAD/CAM dentistry - Process
Usually, CAD / CAM dental restorations are made out of solid ceramic blocks or composite which mostly fit the basic colour of the tooth which is being reconstructed.
Following the preparatory activities and preparation of the parts of the tooth done by the dentist, the impression is taken, depending on the prepared system. Namely, the system scans either plaster model or, as CEREC system does, prepared one and surrounding teeth in patient’s mouth. The image, known as digital impression, delivers information to the computer. Original 3D software creates the replacement for missing parts of the tooth, thus making the virtual restoration. Software sends the virtual information to the milling machine, which operational system resembles so called CNC milling machine which is used in mechanical industry. Milling machine is carving the missing part of the tooth out of the solid ceramic or composite block. Individualization of the restoration is achieved in glazing stove by applying various pigments. Namely, stains and glaze on the surface of manufactured dental restorations may correct usually monochromatic appearance of the restoration. Afterwards, adaptation of dental restoration to the patient’s mouth is done as well as its fixing by cementing.
CAD/CAM dentistry – Previous experience
In traditional restoration processes, porcelain was placed in layers on the metal base. Often, the result was milky white colour of artificial teeth caused by the opaquer layer which was used to cover grey colour of the metal and „famous” dark oxide line, in the vicinity of the gumline. Since these dark metal constructions do not contribute to the natural appearance, non-metal restoration is recommended to the patients, as more aesthetic one.
Only feldspar, lithium disilicate and some composite materials are "radio-transparent", i.e. they do not block x-rays what makes possible for dentists to monitor potential damaging of dental restorations. Zirconium, conventional metals, gold and traditional metal-ceramic crowns block x-rays and disable dentists to make assessment of the condition of dental restorations and abutment teeth over the time.
Finally, dental restorations made by using CAD/CAM technology are more precisely done as opposed to other dental restorations which are made by applying classical methods. Crowns and bridges require extremely precise fitting into the retaining walls of the drilled tooth. This technology offers extreme scanning precision and perfectly correct mathematical calculation of the surface of the drilled stump tooth. According to valid standards, required precision is less than 10 microns, what means that declination from perfection is less than ten thousandth parts of a millimetre. Presently, there is no manually manufactured product which can achive such preciseness without the support of CAD/CAM system in the process of production.
CAD/CAM dentistry - CEREC system
Among CAD/CAM systems which can be found on the market, we are proud to announce that Dental clinic LOPIČIĆ applies CEREC system, produced by German company Sirona. This machine which has improved, latest software and large choice of various ceramic blocks offers extraordinary possibilities. Namel, in one day it is possible to reconstruct large damages on teeth, replace large amalgam fillings with almost indestructible ceramic inlays and onlays which completely reconstruct the morphology of the tooth. There is no need to discuss the precision of the system because interdental contacts and so called “applying” of the dental restoration are determined by the computer. On the other hand, some phases are skipped - such as classical taking of the impression with doughy impression masses which make the patient feel uncomfortable and cause vomiting, as well as famous „metal checks”. This machine, of course, seems perfect. However, it is necessary to have experienced dentist – specialist in dental prosthetics, who will adequately prepare the tooth, because the system will register even the smallest mistake in drilling and preparation and future dental restoration will not be perfect.
Usually, CAD / CAM dental restorations are made out of solid ceramic blocks or composite which mostly fit the basic colour of the tooth which is being reconstructed.
