CVD diamond used in dentistry
Post Date: 28 Jan 2010 Viewed: 590
Modern dentistry is now capable of repairing the damage caused by caries (diseased tooth tissue which causes the formation of cavities) in a minimally invasive way. Besides the removal of caried tissue, the comfort of the patient is a constant concern, and new methods of treatment are being constantly introduced.
The healthy preservation of the teeth in each patient is main objective in dentistry. This aim associated with early diagnosis, safety and comfort is the goal to be reached by all professionals who work in the field of dentistry.Rotating instruments have been used for over 250 years and their continuous technological development has greatly improved the efficiency of cavity preparation [1]. The first dental drills, made of steel, were superseded by tungsten carbide. Nowadays, though, high speed drilling with diamond burrs is the most common method [2].However, the technologies applied in the production of conventional diamond drills are somewhat limited due to the heterogeneous shape of diamond granules, and their short-term durability [3]. Added to that, they tend to remove a good part of the healthy portion of the tooth structure [4]. Within this context, more conservative techniques aiming at removing only the softened, caried, and irreversibly decayed tissue have emerged. Amongst such techniques, one can cite the ultrasonic abrasion system [5], which consists of new CVD diamond coated burrs or tips which can be easily adapted for connection to the handpiece of any ultrasonic instrument commonly used in dental offices for removal of calculus (plaque or tartar) [6].CVD diamond, with its singular properties and relatively simple synthesis process, became an interesting area of investigation. The growth of application areas for the use of CVD diamond is ongoing [7, 8]: applications now include such CVD diamond-coated cutting tools, heat sinks, optical coatings, substrates for multichip module technology and electronic field emitters, in what is becoming a profitable market [7]. The CVD diamond burr for odontological and related use has now joined that list of emerging technologies [9]. A CVD diamond tip coupled to an ultrasound piece makes cavity preparations minimally invasive [10]. This type of tip is manufactured differently to conventional ones, being processed in a reactor that allows the diamond to have sufficient adherence to the metal rod to withstand the vibration effect of ultrasound [11] The comparison between the conventional high-speed rotatory drills using conventional diamond tips and the ultrasonic system with CVD tips is justified in as much as there is nowadays a desire to use procedures which increasingly preserve healthy dental structure and also allow the improvement of tooth/restorative material interaction. As well as producing a literature review, the objective of this article is to enumerate the characteristics of the ultrasonic system using CVD diamond tips and discuss how this leads to a conservative system of caries removal.
Manufacture of CVD diamond tips CVD
Researchers at the National Institute of Space Research (INPE) in Brazil have developed innovative CVD techniques to facilitate the creation of dental diamond tips capable of being coupled with an ultrasound appliance
These tips, called CVDentUS, are produced in a reactor in which a mixture of methane and hydrogen gases results in the formation of a single artificial diamond layer with no space between the grains on the substrate (a molybdenum rod).
Conventional manufacturing methods weld the diamond layer using a galvanic process to the substrate which results in a relatively large area between the diamond grains. This new technique allows the diamond to have sufficient adherence to the metal rod to withstand the vibration effect of ultrasound [11].
Ultrasonic systems have been in existence for over 50 years. However, when it is used for cavity preparation, deficiencies such as the inefficient removal of caried tissue, slow cutting, cost and size factors have worked against it acceptance by dentists [13].
However, some these limitations have now been overcome due to the advent of the CVD diamond tip.
Advantages of CVD diamond tips CVD
Ultrasonically operated CVD diamond tips have the following advantages compared to high speed drilling with conventional diamond burrs:
Vibration, oscillation of the tips;
Angled shape of the shaft of CVD tips facilitates access to the site, therefore allowing a better view
More efficiency in its cutting ability and resistance
Long-term durability because the diamond is chemically broken down into a single piece, dispensing with replacement during preparations
Preservation of healthy dental structure (more conservative method)
Ease and efficiency in caries removal
Less discomfort amongst the patients because noise, vibration, ‘pressure sensation’, and heat are markedly reduced during such a treatment
Less fear and better acceptance by patients, including children
Less need of local anaesthesia
High precision cuts
Prevention of contamination of the tooth by continuous film of diamond without a metallic binder between crystals
Current uses of CVD diamond in dentistry
The manipulation of the ultrasonic system differs from conventional high speed drilling and, although not being difficult to handle, it demands previous practice for the best use. The use of CVD diamond tips is being evaluated in many specialties, for various professionals. It is being widely used in Dentistry and Pediatric Dentistry [15, 25, 28, 29], mainly because of the high precision cuts it provides [14, 20, 22, 29]. These clinical characteristics are very useful as preservation of the healthy dental structure is increasingly being sought [20, 28, 29]. In addition to being a conservative method, the ultrasonic system – making use of CVD diamond tips – minimises discomfort amongst the patients because noise, vibration, ‘pressure sensation’, and heat are markedly reduced during treatment [18, 19, 29]. These aspects are generally associated with fear of dentists and of dental treatment [11, 14, 17, 20], an undesirable situation particularly in the case of pediatric dentistry patients. In periodontics, when performing gingival peeling, and in endodontic surgery, CVD diamond tips were developed with specific angles and small sizes, allowing access to the apex of the tooth for root canal work.
In fixed prostheses, CVD diamond tips are used in periodontic preparation as they do not produce bleeding when in contact with the gingival [30]. In implantology, the tips are used in maxillary sinus lifting, with the advantages that this tips reduce the chance of rupture of the maxillary sinus membrane.
Conclusion
Ultrasonically driven CVD diamond tips have been used with success in several areas of dentistry such as endodontic, implant, pediatric dentistry. But the most interesting application which offers the best advantages is its successful use in minimally invasive dentistry. This new cavity preparation method allows preservation of tooth structure and offers a promising perspective in dentistry with regard to conservative cavity preparation.
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