Steel: A tough, malleable, iron-based alloy containing up to, but no more than, two percent carbon and often other metals. It is used in medicine and dentistry in implants and instrumentation.Stainless Steel: Stainless steel. A steel containing Ni, Cr, or both. It does not tarnish on exposure and is used in corrosive environments. (Grant & Hack's Chemical Dictionary, 5th ed)WeldingDental Alloys: A mixture of metallic elements or compounds with other metallic or metalloid elements in varying proportions for use in restorative or prosthetic dentistry.Corrosion: The gradual destruction of a metal or alloy due to oxidation or action of a chemical agent. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Metallurgy: The science, art, or technology dealing with processes involved in the separation of metals from their ores, the technique of making or compounding the alloys, the techniques of working or heat-treating metals, and the mining of metals. It includes industrial metallurgy as well as metallurgical techniques employed in the preparation and working of metals used in dentistry, with special reference to orthodontic and prosthodontic appliances. (From Jablonski, Dictionary of Dentistry, 1992, p494)Stem Cell Factor: A hematopoietic growth factor and the ligand of the cell surface c-kit protein (PROTO-ONCOGENE PROTEINS C-KIT). It is expressed during embryogenesis and is a growth factor for a number of cell types including the MAST CELLS and the MELANOCYTES in addition to the HEMATOPOIETIC STEM CELLS.Alloys: A mixture of metallic elements or compounds with other metallic or metalloid elements in varying proportions.Materials Testing: The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.Titanium: A dark-gray, metallic element of widespread distribution but occurring in small amounts; atomic number, 22; atomic weight, 47.90; symbol, Ti; specific gravity, 4.5; used for fixation of fractures. (Dorland, 28th ed)Hematopoietic Cell Growth Factors: These growth factors comprise a family of hematopoietic regulators with biological specificities defined by their ability to support proliferation and differentiation of blood cells of different lineages. ERYTHROPOIETIN and the COLONY-STIMULATING FACTORS belong to this family. Some of these factors have been studied and used in the treatment of chemotherapy-induced neutropenia, myelodysplastic syndromes, and bone marrow failure syndromes.Friction: Surface resistance to the relative motion of one body against the rubbing, sliding, rolling, or flowing of another with which it is in contact.Orthodontic Brackets: Small metal or ceramic attachments used to fasten an arch wire. These attachments are soldered or welded to an orthodontic band or cemented directly onto the teeth. Bowles brackets, edgewise brackets, multiphase brackets, ribbon arch brackets, twin-wire brackets, and universal brackets are all types of orthodontic brackets.Chromium: A trace element that plays a role in glucose metabolism. It has the atomic symbol Cr, atomic number 24, and atomic weight 52. According to the Fourth Annual Report on Carcinogens (NTP85-002,1985), chromium and some of its compounds have been listed as known carcinogens.Dental Stress Analysis: The description and measurement of the various factors that produce physical stress upon dental restorations, prostheses, or appliances, materials associated with them, or the natural oral structures.Nickel: A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.Orthodontic Appliance Design: The planning, calculation, and creation of an apparatus for the purpose of correcting the placement or straightening of teeth.Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Dental Prosthesis Retention: Holding a DENTAL PROSTHESIS in place by its design, or by the use of additional devices or adhesives.Proto-Oncogene Proteins c-kit: A protein-tyrosine kinase receptor that is specific for STEM CELL FACTOR. This interaction is crucial for the development of hematopoietic, gonadal, and pigment stem cells. Genetic mutations that disrupt the expression of PROTO-ONCOGENE PROTEINS C-KIT are associated with PIEBALDISM, while overexpression or constitutive activation of the c-kit protein-tyrosine kinase is associated with tumorigenesis.Decontamination: The removal of contaminating material, such as radioactive materials, biological materials, or CHEMICAL WARFARE AGENTS, from a person or object.Crowns: A prosthetic restoration that reproduces the entire surface anatomy of the visible natural crown of a tooth. It may be partial (covering three or more surfaces of a tooth) or complete (covering all surfaces). It is made of gold or other metal, porcelain, or resin.Air Pollutants, Occupational: Air pollutants found in the work area. They are usually produced by the specific nature of the occupation.Chromium Alloys: Specific alloys not less than 85% chromium and nickel or cobalt, with traces of either nickel or cobalt, molybdenum, and other substances. They are used in partial dentures, orthopedic implants, etc.Receptors, Colony-Stimulating Factor: Cell surface receptors for colony stimulating factors, local mediators, and hormones that regulate the survival, proliferation, and differentiation of hemopoietic cells.Tooth Movement: Orthodontic techniques used to correct the malposition of a single tooth.Elastomers: A generic term for all substances having the properties of stretching under tension, high tensile strength, retracting rapidly, and recovering their original dimensions fully. They are generally POLYMERS.Surgical Instruments: Hand-held tools or implements used by health professionals for the performance of surgical tasks.Equipment Reuse: Further or repeated use of equipment, instruments, devices, or materials. It includes additional use regardless of the original intent of the producer as to disposability or durability. It does not include the repeated use of fluids or solutions.Denture Retention: The retention of a denture in place by design, device, or adhesion.Disinfectants: Substances used on inanimate objects that destroy harmful microorganisms or inhibit their activity. Disinfectants are classed as complete, destroying SPORES as well as vegetative forms of microorganisms, or incomplete, destroying only vegetative forms of the organisms. They are distinguished from ANTISEPTICS, which are local anti-infective agents used on humans and other animals. (From Hawley's Condensed Chemical Dictionary, 11th ed)Dental Bonding: An adhesion procedure for orthodontic attachments, such as plastic DENTAL CROWNS. This process usually includes the application of an adhesive material (DENTAL CEMENTS) and letting it harden in-place by light or chemical curing.Diamond: Diamond. A crystalline form of carbon that occurs as hard, colorless or tinted isomeric crystals. It is used as a precious stone, for cutting glass, and as bearings for delicate mechanisms. (From Grant & Hackh's Chemical Dictionary, 5th ed)Equipment Design: Methods of creating machines and devices.Dental Soldering: The joining of pieces of metal through the use of an alloy which has a lower melting point, usually at least 100 degrees Celsius below the fusion temperature of the parts being soldered. In dentistry, soldering is used for joining components of a dental appliance, as in assembling a bridge, joining metals to orthodontic bands, or adding to the bulk of certain structures, such as the establishment of proper contact areas on inlays and crowns with adjacent teeth. (Illustrated Dictionary of Dentistry, 1982)Resin Cements: Dental cements composed either of polymethyl methacrylate or dimethacrylate, produced by mixing an acrylic monomer liquid with acrylic polymers and mineral fillers. The cement is insoluble in water and is thus resistant to fluids in the mouth, but is also irritating to the dental pulp. It is used chiefly as a luting agent for fabricated and temporary restorations. (Jablonski's Dictionary of Dentistry, 1992, p159)Coated Materials, Biocompatible: Biocompatible materials usually used in dental and bone implants that enhance biologic fixation, thereby increasing the bond strength between the coated material and bone, and minimize possible biological effects that may result from the implant itself.Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Polycarboxylate Cement: Water-soluble low-molecular-weight polymers of acrylic or methacrylic acid that form solid, insoluble products when mixed with specially prepared ZnO powder. The resulting cement adheres to dental enamel and is also used as a luting agent.Magnetics: The study of MAGNETIC PHENOMENA.Gold Alloys: Alloys that contain a high percentage of gold. They are used in restorative or prosthetic dentistry.Interleukin-3: A multilineage cell growth factor secreted by LYMPHOCYTES; EPITHELIAL CELLS; and ASTROCYTES which stimulates clonal proliferation and differentiation of various types of blood and tissue cells.Occupational Diseases: Diseases caused by factors involved in one's employment.Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Adhesives: Substances that cause the adherence of two surfaces. They include glues (properly collagen-derived adhesives), mucilages, sticky pastes, gums, resins, or latex.Ceramics: Products made by baking or firing nonmetallic minerals (clay and similar materials). In making dental restorations or parts of restorations the material is fused porcelain. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Boucher's Clinical Dental Terminology, 4th ed)Niobium: Niobium. A metal element atomic number 41, atomic weight 92.906, symbol Nb. (From Dorland, 28th ed)Health Policy: Decisions, usually developed by government policymakers, for determining present and future objectives pertaining to the health care system.Politics: Activities concerned with governmental policies, functions, etc.District of Columbia: A federal area located between Maryland and Virginia on the Potomac river; it is coextensive with Washington, D.C., which is the capital of the United States.WashingtonGreat BritainTravel: Aspects of health and disease related to travel.Democracy: A system of government in which there is free and equal participation by the people in the political decision-making process.