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Dental materials chemical properties

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. [Pg.373]

Fluorine is an essential element involved in several enzymatic reactions in various organs, it is present as a trace element in bone mineral, dentine and tooth enamel and is considered as one of the most efficient elements for the prophylaxis and treatment of dental caries. In addition to their direct effect on cell biology, fluoride ions can also modify the physico-chemical properties of materials (solubility, structure and microstructure, surface properties), resulting in indirect biological effects. The biological and physico-chemical roles of fluoride ions are the main reasons for their incorporation in biomaterials, with a pre-eminence for the biological role and often both in conjunction. This chapter focuses on fluoridated bioceramics and related materials, including cements. The specific role of fluorinated polymers and molecules will not be reviewed here. [Pg.281]

The properties exhibited by polyelectrolytes make them nearly-ideal candidates for dental material formulations. Dental polyelectrolytes are generally considered to be nontoxic and are able to adsorb chemically to the hydrophilic surface of tooth material through ionic interactions. Ionic cross-linking of the polyelectrolyte with multivalent cations (Zn2+, Mg2+, Al3+, Ca2+) results in the formation of a rigid and insoluble cement matrix. The stability and strength of the cement is attributed to the fact that, if a bond is broken, it can be reformed as long as the other bonds are maintained. Even today, polyelectrolytes are the only materials which are known with certainty to form a bond, which is stable with time, to tooth material [120]. In addition to long-term stability, many polyelectrolytes are translucent and possess cariostatic properties [121]. [Pg.14]

A material is a biomaterial when it meets certain requirements it has to have the right physical and chemical properties and, in addition, be biocompatible, which means that it must not be rejected by the body. The material may not release any substances which might activate the host s immune system. As indicated earlier, the first biomaterials were metals and these still play an important part. Of all metals and alloys, titanium appears to be accepted best by tissues. Actually this is rather peculiar, as titanium is relatively rare in vegetable and animal tissue but relatively abundant in the earth s crust (0.2% of the mass of the earth s crust is titanium only six other metals are even more abundant). For some time now, titanium has been used in dental surgery and in attaching and replacing bones and joints. [Pg.263]

Properties of injection-molded parts can be unique. Given a metal or plastic s typical properties, injection molding imparts some of its own. Because of flow patterns, molecular orientation, and other factors, molded part properties are often different than those of the base material. An example of the benefits of orientation is the living hinge , the flexible plastic hinge foimd on spice, shampoo, and dental floss containers. Properties of injection-molded parts can be flexible or stiff, soft or hard, tough or brittle, clear or opaque, specific chemically resistant and flame retardant. Parts can be tinted, colored, plated with varions metals, and recycled. [Pg.3951]

Polymers are widely used as implant materials because they have physical properties that are similar to those of natural tissues. Examples are long-term and shortterm implants such as blood vessels, heart valves, membranes, mesh prostheses, corneas, tracheal prostheses, dental materials, parts of the nose and ear, knee and hip joints, and others. The synthetic polymers used include polyethylene (PE), particularly ultrahigh molecular weight PE (UHMWPE), poly(ethylene terephthal-ate) (PET), poly(tetrafluoroethylene) (PTFE), polyurethane (PU), and poly(methyl methacrylate) (PMMA). The necessary sterilization before implantation can be performed by y-irradiation, heat (steam), or chemical treatment (ethylene oxide), which should not cause any structural degradation of the polymers. Current challenges in research include the development of biomimetic materials that match both the mechanical and biological properties of their natural counterparts. [Pg.488]

Name a necessary chemical pixrperty and a necessary physical property of dental materials. [Pg.961]

The resin matrix of dental materials has important influence on the chemical and physical properties of light cure resins. The organic formulations also include photoiniti-ating systems that absorb light. From there free radicals start the conversion of the oligomer blend to a polymeric cross-linked network. Camphorquinone (CQ) is widely used in dental resin mixed with an amine. However, CQ is a solid, yellow compound with an unbleachable chromophore. [Pg.532]

Acrylic Resins. The first synthetic polymer denture material, used throughout much of the 20th century, was based on the discovery of vulcanised mbber in 1839. Other polymers explored for denture and other dental uses have included ceUuloid, phenolformaldehyde resins, and vinyl chloride copolymers. Polystyrene, polycarbonates, polyurethanes, and acryHc resins have also been used for dental polymers. Because of the unique combination of properties, eg, aesthetics and ease of fabrication, acryHc resins based on methyl methacrylate and its polymer and/or copolymers have received the most attention since their introduction in 1937. However, deficiencies include excessive polymerization shrinkage and poor abrasion resistance. Polymers used in dental appHcation should have minimal dimensional changes during and subsequent to polymerization exceUent chemical, physical, and color stabiHty processabiHty and biocompatibiHty and the abiHty to blend with contiguous tissues. [Pg.488]

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. [Pg.495]

Fisher, F. J. McCabe, J. F. (1978). Calcium hydroxide base materials an investigation into the relationship between chemical structures and antibacterial properties. British Dental Journal, 144, 341-4. [Pg.354]

Traditional materials for orthopedic and dental applications have been selected based on their mechanical properties and ability to remain inert in vivo this selection process has provided materials that satisfied physiological loading conditions but did not duplicate the mechanical, chemical, and architectural properties of bone. Most importantly, to date, failure of conventional orthopedic and dental implant materials is often due to insufficient bonding to juxtaposed bone (that is, insufficient osseointegration). [Pg.148]

Orthopedic and dental implant materials bioceramics, 145-146 chemical modifications, 147-148 comparing mechanical properties of, and bone, 146 conventional, 127 costs, 126-127 current materials, 145-148 fate of implanted device, 140-141 integration into surrounding tissue, 127 integrin expression on osteoblasts, 144 integrins, 143-144 metals, ceramics, and polymers, 145 next generation, 127,148-159... [Pg.212]


See other pages where Dental materials chemical properties is mentioned: [Pg.146]    [Pg.920]    [Pg.266]    [Pg.349]    [Pg.15]    [Pg.767]    [Pg.3307]    [Pg.176]    [Pg.7562]    [Pg.8492]    [Pg.222]    [Pg.844]    [Pg.659]    [Pg.5]    [Pg.832]    [Pg.1422]    [Pg.256]    [Pg.419]    [Pg.429]    [Pg.430]    [Pg.481]    [Pg.321]    [Pg.29]    [Pg.480]    [Pg.541]    [Pg.979]    [Pg.1481]    [Pg.126]    [Pg.127]    [Pg.145]    [Pg.146]    [Pg.15]    [Pg.128]    [Pg.129]    [Pg.147]    [Pg.148]   
See also in sourсe #XX -- [ Pg.299 , Pg.300 ]




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