Dental implantation

Biomedical. Heart-valve parts are fabricated from pyrolytic carbon, which is compatible with living tissue. Such parts are produced by high temperature pyrolysis of gases such as methane. Other potential biomedical apphcations are dental implants and other prostheses where a seal between the implant and the living biological surface is essential. Plasma and arc-wire sprayed coatings are used on prosthetic devices, eg, hip implants, to achieve better bone/tissue attachments (see Prosthetic and BiOLffiDiCALdevices). 

Therapeutic dental materials. Calcium phosphate materials. Dental implants. 

Cobalt—Chromium Alloys. Co—Cr and Ni—Cr alloys are used predominately for the casting of removable partial dentures fixed partial dentures (bridges), crowns, and inlays are also cast. Because of high hardness, corrosion resistance, and wear resistance cobalt-chromium alloys are used for bite adjustments and as serrated inserts in plastic teeth used in fliU dentures. These alloys are well tolerated by the body and also are used for dental implants and orthopedic implant alloys. 

Regulation. Dental implants are regulated by the Food and Dmg Administration. AH dental implants faH iato the FDA class III which covers devices that are life sustaioiag, life supportiag, or are implanted iato the body and have the potential to cause unreasonable risk, illness, or iajury. Devices ia class III are requited to have appHcatioas for premarket approval (315). There are 15 to 20 companies that have FDA marketing clearance for specific dental implants, based on substantial equivalency to implants marketed prior to 1976, and approximately one third of these companies are foreign. Marketing clearance is not the same as premarket approval. 

Requirements. Requirements for dental implant materials are the same as those for orthopedic uses. The first requirement is that the material used ia the implant must be biocompatible and not cause any adverse reaction ia the body. The material must be able to withstand the environment of the body, and not degrade and be unable to perform the iatended function. 

There are a number of designs for dental implants. The patient must have ample bone and the proper design should be chosen for each iadividual. Another factor that affects the success of dental implants is patient care of the implant and dental hygiene. 

The American Society for Testing and Materials (ASTM) F4 Committee on Medical Materials and Devices has developed specifications for chemical composition, mechanical properties, and other factors. Standard test methods also are available from ASTM, 1916 Race Street, Philadelphia. The quaHty of castings is important for dental implants, and standards to define this would be useful. 

Hydroxyapaite, the mineral constituent of bone, is appHed to the surfaces of many dental implants for the purpose of increasing initial bone growth. Some iavestigators beHeve that an added benefit is that the hydroxyapatite shields the bone from the metal. However, titanium and its aHoy, Ti-6A1-4V, are biocompatible and have anchored successfuHy as dental implants without the hydroxyapatite coating. 

Surface preparation of the dental implant prior to implantation wiH have an effect on corrosion behavior, initial metal ion release, and interface tissue response (316). The titanium and titanium aHoy dental implants in present use have many forms to assist bone ingrowth attachment including cylinders with holes, screw threaded surfaces, porous surfaces, and other types of roughened surfaces. Methods used to produce porous surfaces iaclude arc plasma... 

Types of Dental Implants. Indications for a specific type of implant are based primarily on the amount of bone available to support the implant. Also to be considered is the implant proven most successful. Three types of implants are discussed here. 

National Institutes ofHealth, Consensus Development Conference Statement on Dental Implants, (1988). 

A. C. Fraker and co-workers, in M. J. Fagan, Jr. and co-workers, eds.. Implant Prosthodontics Surgical and Prosthetic Techniquesfor Dental Implants, Yearbook Medical Pubhshers, Littieton, Mass., 1991, pp. 293—304. 

D. Adams and D. F. WiUiams,M Revieiv of Dental Implants, Dental Update, Upstate PubHcations, Ltd., London, 1985, p. 480. 

Various materials are used in dental prosthetic practice for the preparation of dental implants, crowns, and bridges. Some of these materials contain copper, which is added in order to improve mechanical or/and chemical properties, but some of them may contain the copper as an impurity. Considering the fact that dental implants remain in the oral cavity for a long time, and that they are exposed to the corrosive action of oral fluids and various kinds of food and beverages, it is necessary to check their possible harmful effects upon the human health. 

Titanium and its compounds are nontoxic and immune to attack by body fluids. These features account for the use of the metal in knee and hip replacements as well as dental implants. 

PAEK) plastic that cost 40/lb was being market in dental implants, bone replacement joints, and components for the hip, elbow, finger, knee, spine, and other body products. And so all these type of actions continue in the plastic industry worldwide. 

The major biological application of isotropic carbon is in heart valves. The material is performing well and several hundred thousand units have been produced so far. Other applications include dental implants, ear prostheses, and as a coating for in-dwelling catheters. 

Thomas J. Webster, Nanophase Ceramics The Future Orthopedic and Dental Implant Material Yu-Ming Lin, Mildred S. Dresselhaus, and Jackie Y. Ying, Fabrication, Structure, and Transport Properties if Nanowires... 

Dental glass-ceramics, 8 276-277 Dental implants, 8 342-345 Dental industry, electroless deposition in, 9 700... 

Endohedral fullerenes, 12 230-231 chemistry of, 12 253 Endonucleases, artificial, 17 636 Endoperoxides, 18 442—443 Endopolygalacturonase, 11 598 Endo-receptors, convergent, 16 774 Endosseous dental implants, 8 344 Endothall (Aquathol Granular, Aquathol K), 13 315... 

Submersible pumps, 21 65, 66 Submicrometer size fibers, 11 186 Subperiosteal dental implants, 8 ... 

Transmitters, smart pressure, 20 663-665 Transosteal dental implants, 3 345 Transparency... 

The first ever injectable crude biomaterial, that is a dental implant, appeared early in ad 6oo (Fig. 12.1). During those times, Mayan people trimmed seashells into artificial teeth to replace missing teeth (Michael, 2006 Ratner et al., 2004). Early biomaterials also led to problems, including sterilization, toxicity, inflammation, and immunological issues. Since the Mayan s initial use of artificial teeth, biomaterials have evolved to be used in modem artificial hearts, hip and knee pros-theses, artificial kidneys, and breast implants. Materials used in these applications include titanium, silicons, polyurethanes, teflon, polybiodegradable polymers, and most recently bio-nanomaterials (Pearce et al., 2007)... 

Periodontal disease is characterized by a sequence of chronic oral inflammation and excessive alveolar bone resorption (i.e., receding alveolar bone) that results in root surface exposure of teeth, increased sensitivity, eventual detachment of the periodontal ligament, and subsequent tooth loss. Alveolar ridge bone exhibits intrinsic porosity, a structural fragility, and a proximity to vasculature that in effect virtually ensures it has the potential to be a vulnerable site in times of rapid bone resorption, much like the trabecular-rich regions in the hip and spine. Subsequent retention of the quantity and quality of bone in edentulous jaws also becomes critically important in terms of being able to provide surface support for dental implants and dentures that are desirable for both functional and cosmetic purposes (Bodic et al., 2005) (Figure 6.4). 

Polyelectrolytes have been widely used for the preparation of controlled/sus-tained release of drugs. It is therefore not surprising that attempts have been made to use dental implants for the slow-release of antibiotics and fluorides. It... 

Metallic biomaterials (metals such as Ti or its alloys and others) are used for the manufacture of orthopaedic implants due to their excellent biocompatibility with respect to electrical and thermal conductivity and their mechanical properties, e.g., for hard tissue replacement such as total hip and knee joints, for fracture healing aids such as bone plates and screws or dental implants. For example, Co-Cr-Mo alloys are employed for metal-on-metal hip bearings in total joint replacements. Problems with implants occur because of ion release in patients with metal implants. To control this ion release, the ultratrace determination of Co, Cr and Mo in the blood (or serum) and urine of patients with Co-Cr-Mo alloy hip implants is carried out routinely in the author s laboratory. The trace metal determination of Co, Cr and Mo in complex matrices such as urine and blood by ICP-MS is not trivial due to the low concentrations expected in the sub-ngmF1 range, the possible danger of contamination during sample collection, sample preparation and the... 

An accurate determination of copper and zinc traces in human serum samples from the International Measurement Evaluation Programme-17 launched by IRMM (Geel) has been made by isotope dilution TIMS.38 An analytical method for the multi-element determination of metals (Ti, V, Cr, Co, Ni and Mo) potentially released from dental implants and prostheses into human body fluids (in blood and urine) by ICP-MS (double-focusing sector field instrument and quadrupole instrument with octopole collision cell) for medical studies was developed in Sanz-Medel s group.39 The Cr and Co concentrations found in blood samples of patients with chromium-cobalt based alloy varied in the sub-p,gl 1 range and were not significantly higher than the basal levels found by other authors.40... 

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