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)
Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)
Procedures for the improvement or enhancement of the appearance of the visible parts of the body.
An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.
Synthetic resins, containing an inert filler, that are widely used in dentistry.
The phenomenon of youthfulness, vitality, and freshness being restored. This can apply to appearance, TISSUES, organ functions, or other areas.
Poly-2-methylpropenoic acids. Used in the manufacture of methacrylate resins and plastics in the form of pellets and granules, as absorbent for biological materials and as filters; also as biological membranes and as hydrogens. Synonyms: methylacrylate polymer; poly(methylacrylate); acrylic acid methyl ester polymer.
The quality or state of being able to be bent or creased repeatedly. (From Webster, 3d ed)
Compounds similar to hydrocarbons in which a tetravalent silicon atom replaces the carbon atom. They are very reactive, ignite in air, and form useful derivatives.
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.
Acrylic acids or acrylates which are substituted in the C-2 position with a methyl group.
A group of thermoplastic or thermosetting polymers containing polyisocyanate. They are used as ELASTOMERS, as coatings, as fibers and as foams.
The process of aging due to changes in the structure and elasticity of the skin over time. It may be a part of physiological aging or it may be due to the effects of ultraviolet radiation, usually through exposure to sunlight.
Materials used in the production of dental bases, restorations, impressions, prostheses, etc.
The reaction product of bisphenol A and glycidyl methacrylate that undergoes polymerization when exposed to ultraviolet light or mixed with a catalyst. It is used as a bond implant material and as the resin component of dental sealants and composite restorative materials.
The mechanical property of material that determines its resistance to force. HARDNESS TESTS measure this property.
Hard, amorphous, brittle, inorganic, usually transparent, polymerous silicate of basic oxides, usually potassium or sodium. It is used in the form of hard sheets, vessels, tubing, fibers, ceramics, beads, etc.
Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.
Nanometer-scale composite structures composed of organic molecules intimately incorporated with inorganic molecules. (Glossary of Biotechnology and Nanobiotechology Terms, 4th ed)
Inorganic compounds that contain barium as an integral part of the molecule.
A trace element that is required in bone formation. It has the atomic symbol Sn, atomic number 50, and atomic weight 118.71.
Characteristics or attributes of the outer boundaries of objects, including molecules.
A restoration designed to remain in service for not less than 20 to 30 years, usually made of gold casting, cohesive gold, or amalgam. (Jablonski, Dictionary of Dentistry, 1992)
Creation of a smooth and glossy surface finish on a denture or amalgam.
Polymers of high molecular weight which at some stage are capable of being molded and then harden to form useful components.
The maximum compression a material can withstand without failure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p427)
Relating to the size of solids.
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.
Occlusal wear of the surfaces of restorations and surface wear of dentures.
The branch of surgery concerned with restoration, reconstruction, or improvement of defective, damaged, or missing structures.
Inorganic compounds that contain silicon as an integral part of the molecule.
Polymerized methyl methacrylate monomers which are used as sheets, moulding, extrusion powders, surface coating resins, emulsion polymers, fibers, inks, and films (From International Labor Organization, 1983). This material is also used in tooth implants, bone cements, and hard corneal contact lenses.
Inorganic compounds that contain carbon as an integral part of the molecule but are not derived from hydrocarbons.
The maximum stress a material subjected to a stretching load can withstand without tearing. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p2001)
Calcium fluoride. Occurring in nature as the mineral fluorite or fluorspar. It is the primary source of fluorine and its compounds. Pure calcium fluoride is used as a catalyst in dehydration and dehydrogenation and is used to fluoridate drinking water. (From Merck Index, 11th ed)
Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.
Quartz (SiO2). A glassy or crystalline form of silicon dioxide. Many colored varieties are semiprecious stones. (From Grant & Hackh's Chemical Dictionary, 5th ed)
The degree of approximation or fit of filling material or dental prosthetic to the tooth surface. A close marginal adaptation and seal at the interface is important for successful dental restorations.
A form of alveolitis or PNEUMONITIS caused by hypersensitivity to high level of inhaled nitrogen oxides, decomposition products of silage.
Fluoride-releasing restorative materials made by the sintering of metal (usually silver) particles to glass ionomer powder. Glass ionomers are fluoride-releasing cements that are not very durable. Sintering of the metal particles is a means of improving those physical properties that will make the glass ionomer cement more durable.
A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.
Identification and measurement of ELEMENTS and their location based on the fact that X-RAYS emitted by an element excited by an electron beam have a wavelength characteristic of that element and an intensity related to its concentration. It is performed with an electron microscope fitted with an x-ray spectrometer, in scanning or transmission mode.
A polymer obtained by reacting polyacrylic acid with a special anion-leachable glass (alumino-silicate). The resulting cement is more durable and tougher than others in that the materials comprising the polymer backbone do not leach out.
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.
Substances that inhibit or arrest DENTAL CARIES formation. (Boucher's Clinical Dental Terminology, 4th ed)
A fabricated tooth substituting for a natural tooth in a prosthesis. It is usually made of porcelain or plastic.
Metals that constitute group 1(formerly group Ia) of the periodic table. They are the most strongly electropositive of the metals. Note that HYDROGEN is not considered an alkali metal even though it falls under the group 1 heading in the periodic table.
Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.
A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.
The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.
The branch of philosophy dealing with the nature of the beautiful. It includes beauty, esthetic experience, esthetic judgment, esthetic aspects of medicine, etc.
A mixture of metallic elements or compounds with other metallic or metalloid elements in varying proportions for use in restorative or prosthetic dentistry.
A natural high-viscosity mucopolysaccharide with alternating beta (1-3) glucuronide and beta (1-4) glucosaminidic bonds. It is found in the UMBILICAL CORD, in VITREOUS BODY and in SYNOVIAL FLUID. A high urinary level is found in PROGERIA.
Either of the two fleshy, full-blooded margins of the mouth.
The forcing into the skin of liquid medication, nutrient, or other fluid through a hollow needle, piercing the top skin layer.
A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.
Silicon polymers that contain alternate silicon and oxygen atoms in linear or cyclic molecular structures.
Zirconium. A rather rare metallic element, atomic number 40, atomic weight 91.22, symbol Zr. (From Dorland, 28th ed)
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)
A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The hardening or polymerization of bonding agents (DENTAL CEMENTS) via exposure to light.
Metals that constitute the group 2 (formerly group IIa) of the periodic table.
A peroxide derivative that has been used topically for BURNS and as a dermatologic agent in the treatment of ACNE and POISON IVY DERMATITIS. It is used also as a bleach in the food industry.
Any of the numerous types of clay which contain varying proportions of Al2O3 and SiO2. They are made synthetically by heating aluminum fluoride at 1000-2000 degrees C with silica and water vapor. (From Hawley's Condensed Chemical Dictionary, 11th ed)
A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
The generic term for salts derived from silica or the silicic acids. They contain silicon, oxygen, and one or more metals, and may contain hydrogen. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th Ed)
Benzoic acids, salts, or esters that contain an amino group attached to carbon number 4 of the benzene ring structure.
Chronic inflammation and granuloma formation around irritating foreign bodies.
The spectrometric analysis of fluorescent X-RAYS, i.e. X-rays emitted after bombarding matter with high energy particles such as PROTONS; ELECTRONS; or higher energy X-rays. Identification of ELEMENTS by this technique is based on the specific type of X-rays that are emitted which are characteristic of the specific elements in the material being analyzed. The characteristic X-rays are distinguished and/or quantified by either wavelength dispersive or energy dispersive methods.
Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).
A broad family of synthetic organosiloxane polymers containing a repeating silicon-oxygen backbone with organic side groups attached via carbon-silicon bonds. Depending on their structure, they are classified as liquids, gels, and elastomers. (From Merck Index, 12th ed)
A broad class of substances encompassing all those that do not include carbon and its derivatives as their principal elements. However, carbides, carbonates, cyanides, cyanates, and carbon disulfide are included in this class.
Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.
The quality or state of being wettable or the degree to which something can be wet. This is also the ability of any solid surface to be wetted when in contact with a liquid whose surface tension is reduced so that the liquid spreads over the surface of the solid.
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.
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.
An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
Ytterbium. An element of the rare earth family of metals. It has the atomic symbol Yb, atomic number 70, and atomic weight 173. Ytterbium has been used in lasers and as a portable x-ray source.
Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.
Numerical expression indicating the measure of stiffness in a material. It is defined by the ratio of stress in a unit area of substance to the resulting deformation (strain). This allows the behavior of a material under load (such as bone) to be calculated.
Chemical reaction in which monomeric components are combined to form POLYMERS (e.g., POLYMETHYLMETHACRYLATE).
Usually inert substances added to a prescription in order to provide suitable consistency to the dosage form. These include binders, matrix, base or diluent in pills, tablets, creams, salves, etc.
Passage of light through body tissues or cavities for examination of internal structures.
The dried seeds, bark, root, stems, buds, leaves, or fruit of aromatic plants used to season food.
Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.
Electrodes which can be used to measure the concentration of particular ions in cells, tissues, or solutions.
The anterior portion of the head that includes the skin, muscles, and structures of the forehead, eyes, nose, mouth, cheeks, and jaw.
Inorganic salts of hydrofluoric acid, HF, in which the fluorine atom is in the -1 oxidation state. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Sodium and stannous salts are commonly used in dentifrices.
Alloys that contain a high percentage of gold. They are used in restorative or prosthetic dentistry.
The rate dynamics in chemical or physical systems.
The hard portion of the tooth surrounding the pulp, covered by enamel on the crown and cementum on the root, which is harder and denser than bone but softer than enamel, and is thus readily abraded when left unprotected. (From Jablonski, Dictionary of Dentistry, 1992)
Substances made up of an aggregation of small particles, as that obtained by grinding or trituration of a solid drug. In pharmacy it is a form in which substances are administered. (From Dorland, 28th ed)
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.
Inorganic compounds that contain calcium as an integral part of the molecule.
Resistance and recovery from distortion of shape.
The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.
A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.
A medical specialty concerned with the skin, its structure, functions, diseases, and treatment.
The retention of a denture in place by design, device, or adhesion.
The resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A metallic element that has the atomic number 13, atomic symbol Al, and atomic weight 26.98.
Viscoelastic solutions that are injected into JOINTS in order to alleviate symptoms of joint-related disorders such as OSTEOARTHRITIS.
Drugs used to treat or prevent skin disorders or for the routine care of skin.
Synthetic or natural materials for the replacement of bones or bone tissue. They include hard tissue replacement polymers, natural coral, hydroxyapatite, beta-tricalcium phosphate, and various other biomaterials. The bone substitutes as inert materials can be incorporated into surrounding tissue or gradually replaced by original tissue.
Colloids with a solid continuous phase and liquid as the dispersed phase; gels may be unstable when, due to temperature or other cause, the solid phase liquefies; the resulting colloid is called a sol.
Congenital or acquired asymmetry of the face.
The properties and processes of materials that affect their behavior under force.
Implants constructed of materials designed to be absorbed by the body without producing an immune response. They are usually composed of plastics and are frequently used in orthopedics and orthodontics.
Measurement of cells' substrate utilization and biosynthetic output for modeling of METABOLIC NETWORKS.
Introduction of substances into the body using a needle and syringe.
A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.
Restorations of metal, porcelain, or plastic made to fit a cavity preparation, then cemented into the tooth. Onlays are restorations which fit into cavity preparations and overlay the occlusal surface of a tooth or teeth. Onlays are retained by frictional or mechanical factors.
Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.
A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.
A partial denture designed and constructed to be removed readily from the mouth.
Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading.
A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.19, symbol Pb. (Dorland, 28th)
Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.
The methyl esters of methacrylic acid that polymerize easily and are used as tissue cements, dental materials, and absorbent for biological substances.
An oxide of aluminum, occurring in nature as various minerals such as bauxite, corundum, etc. It is used as an adsorbent, desiccating agent, and catalyst, and in the manufacture of dental cements and refractories.
The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.
Elements of limited time intervals, contributing to particular results or situations.
The act of cleaning teeth with a brush to remove plaque and prevent tooth decay. (From Webster, 3d ed)
Light sources used to activate polymerization of light-cured DENTAL CEMENTS and DENTAL RESINS. Degree of cure and bond strength depends on exposure time, wavelength, and intensity of the curing light.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A group of elements that include SCANDIUM; YTTRIUM; and the LANTHANOID SERIES ELEMENTS. Historically, the rare earth metals got their name from the fact that they were never found in their pure elemental form, but as an oxide. In addition they were very difficult to purify. They are not truly rare and comprise about 25% of the metals in the earth's crust.
The placing of a body or a part thereof into a liquid.
The preparation, mixing, and assembling of a drug. (From Remington, The Science and Practice of Pharmacy, 19th ed, p1814)
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
An operation in which carious material is removed from teeth and biomechanically correct forms are established in the teeth to receive and retain restorations. A constant requirement is provision for prevention of failure of the restoration through recurrence of decay or inadequate resistance to applied stresses. (Boucher's Clinical Dental Terminology, 4th ed, p239-40)
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
An element of the alkaline earth family of metals. It has the atomic symbol Sr, atomic number 38, and atomic weight 87.62.
The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.
Silver. An element with the atomic symbol Ag, atomic number 47, and atomic weight 107.87. It is a soft metal that is used medically in surgical instruments, dental prostheses, and alloys. Long-continued use of silver salts can lead to a form of poisoning known as ARGYRIA.
Measurement of the index of refraction (the ratio of the velocity of light or other radiation in the first of two media to its velocity in the second as it passes from one into the other).
Solid dosage forms, of varying weight, size, and shape, which may be molded or compressed, and which contain a medicinal substance in pure or diluted form. (Dorland, 28th ed)
Chemical compound used to initiate polymerization of dental resins by the use of DENTAL CURING LIGHTS. It absorbs UV light and undergoes decomposition into free radicals that initiate polymerization process of the resins in the mix. Each photoinitiator has optimum emission spectrum and intensity for proper curing of dental materials.
Neutral or negatively charged ligands bonded to metal cations or neutral atoms. The number of ligand atoms to which the metal center is directly bonded is the metal cation's coordination number, and this number is always greater than the regular valence or oxidation number of the metal. A coordination complex can be negative, neutral, or positively charged.
A nonmetallic element with atomic symbol C, atomic number 6, and atomic weight [12.0096; 12.0116]. It may occur as several different allotropes including DIAMOND; CHARCOAL; and GRAPHITE; and as SOOT from incompletely burned fuel.
A hard thin translucent layer of calcified substance which envelops and protects the dentin of the crown of the tooth. It is the hardest substance in the body and is almost entirely composed of calcium salts. Under the microscope, it is composed of thin rods (enamel prisms) held together by cementing substance, and surrounded by an enamel sheath. (From Jablonski, Dictionary of Dentistry, 1992, p286)
The fusion of ceramics (porcelain) to an alloy of two or more metals for use in restorative and prosthodontic dentistry. Examples of metal alloys employed include cobalt-chromium, gold-palladium, gold-platinum-palladium, and nickel-based alloys.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Any technique by which an unknown color is evaluated in terms of standard colors. The technique may be visual, photoelectric, or indirect by means of spectrophotometry. It is used in chemistry and physics. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Polymeric resins derived from OXIRANES and characterized by strength and thermosetting properties. Epoxy resins are often used as dental materials.
An inner coating, as of varnish or other protective substance, to cover the dental cavity wall. It is usually a resinous film-forming agent dissolved in a volatile solvent, or a suspension of calcium hydroxide in a solution of a synthetic resin. The lining seals the dentinal tubules and protects the pulp before a restoration is inserted. (Jablonski, Illustrated Dictionary of Dentistry, 1982)
Materials placed inside a root canal for the purpose of obturating or sealing it. The materials may be gutta-percha, silver cones, paste mixtures, or other substances. (Dorland, 28th ed, p631 & Boucher's Clinical Dental Terminology, 4th ed, p187)
Cements that act through infiltration and polymerization within the dentinal matrix and are used for dental restoration. They can be adhesive resins themselves, adhesion-promoting monomers, or polymerization initiators that act in concert with other agents to form a dentin-bonding system.
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... and adding filler metal. The filler rod is withdrawn from the weld pool each time the electrode advances, but it is always kept ... To maintain a clean weld pool during welding, the shielding gas flow should be sufficient and consistent so that the gas covers ... dross-filled welds. Processes using flux-covered electrodes did not satisfactorily protect the weld area from contamination. To ... A filler metal is normally used, though some welds, known as autogenous welds, or fusion welds do not require it. When helium ...
... the flux provides molten slag which covers the filler as it travels from electrode to the weld pool. Once part of the weld pool ... Weld spatter, while not affecting the integrity of the weld, damages its appearance and increases cleaning costs. Secondary ... Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMA or MMAW), flux shielded arc welding or ... of weld metal per hour. Houldcroft, P. T. (1973) [1967]. "Chapter 3: Flux-Shielded Arc Welding". Welding Processes. Cambridge ...
... and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. A constant-current ... To maintain a clean weld pool during welding, the shielding gas flow should be sufficient and consistent so that the gas covers ... dross-filled welds.[5] Processes using flux-covered electrodes did not satisfactorily protect the weld area from contamination ... a vast assortment of welding filler metal is available to the welding engineer. In fact, no other welding process permits the ...
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properties and can be welded; the best results are obtained with gas metal arc welding. Gas metal arc welding ... The filler metal is brought slightly above its melting temperature while protected by a suitable atmosphere, usually a flux... ... Bioleaching is the extraction of specific metals from their ores through the use of living organisms. This is much cleaner than ... Gas metal arc welding , sometimes referred to by its subtypes metal inert gas welding or metal active gas welding, is a semi- ...
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  • As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination. (
  • As the electrode melts, the flux covering disintegrates, giving off shielding gases that protect the weld area from oxygen and other atmospheric gases. (
  • [5] Processes using flux-covered electrodes did not satisfactorily protect the weld area from contamination. (
  • The process is used primarily to weld iron and steels (including stainless steel) but aluminium, nickel and copper alloys can also be welded with this method. (
  • The 1970s ushered in a new generation of more versatile alloy steels which could be welded mechanically, thereby increasing the availability of light and inexpensive frames. (
  • Gas tungsten arc welding ( GTAW ), also known as tungsten inert gas ( TIG ) welding , is an arc welding process that uses a non-consumable tungsten electrode to produce the weld . (
  • C. L. Coffin had the idea of welding in an inert gas atmosphere in 1890, but even in the early 20th century, welding non-ferrous materials such as aluminium and magnesium remained difficult because these metals react rapidly with the air and result in porous, dross -filled welds. (
  • [7] Meredith named the process Heliarc because it used a tungsten electrode arc and helium as a shielding gas, but it is often referred to as tungsten inert gas welding (TIG). (
  • Welding without gas Where ordinary mild steel mig welding wire needs an inert gas shield to prevent it from oxidising when melted, gasless MIG wire has a flux core which forms the shield around the weld to keep oxygen out. (
  • Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMA or MMAW), flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld. (
  • An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. (
  • The workpiece and the electrode melts forming a pool of molten metal (weld pool) that cools to form a joint. (
  • In 1885, Nikolay Benardos and Stanisław Olszewski developed carbon arc welding, obtaining American patents from 1887 showing a rudimentary electrode holder. (
  • In 1888, the consumable metal electrode was invented by Nikolay Slavyanov. (
  • Later in 1890, C. L. Coffin received U.S. Patent 428,459 for his arc welding method that utilized a metal electrode. (
  • The process, like SMAW, deposited melted electrode metal into the weld as filler. (
  • To strike the electric arc, the electrode is brought into contact with the workpiece by a very light touch of the electrode to the base metal. (
  • This initiates the arc and thus the melting of the workpiece and the consumable electrode, and causes droplets of the electrode to be passed from the electrode to the weld pool. (
  • The orientation of the electrode to workpiece is where most stumble, if the electrode is held at a perpendicular angle to the workpiece the tip will likely stick to the metal which will fuse the electrode to the workpiece which will cause it to heat up very rapidly. (
  • The tip of the electrode needs to be at a lower angle to the workpiece, which allows the weld pool to flow out of the arc. (
  • In addition, the flux provides molten slag which covers the filler as it travels from electrode to the weld pool. (
  • As welding progresses and the electrode melts, the welder must periodically stop welding to remove the remaining electrode stub and insert a new electrode into the electrode holder. (
  • The weld area and electrode is protected from oxidation or other atmospheric contamination by an inert shielding gas ( argon or helium ), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. (
  • Initially, the electrode overheated quickly and, despite tungsten's high melting temperature , particles of tungsten were transferred to the weld. (
  • [6] To address this problem, the polarity of the electrode was changed from positive to negative, but the change made it unsuitable for welding many non-ferrous materials. (
  • This common method of welding was invented in the year 1802 and involves the use of a consumable electrode that has a flux-coated core wire that gives electric current. (
  • After you learn basic welding safety, the basics of tig welding, machine settings, electrode basics, and metal preparation, its time to light up. (
  • Unlike arc welding (stick welding) where the electrode burns away and becomes shorter and requires the welder to manually maintain the arc length, mig welding only requires the welder to move steadily along a seam while maintaining the same tip to arc distance. (
  • Manual gas tungsten arc welding is a relatively difficult welding method, due to the coordination required by the welder. (
  • Similar to torch welding, GTAW normally requires two hands, since most applications require that the welder manually feed a filler metal into the weld area with one hand while manipulating the welding torch in the other. (
  • As a welder, you need to know all the welding process. (
  • Because of the versatility of the process and the simplicity of its equipment and operation, shielded metal arc welding is one of the world's first and most popular welding processes. (
  • It dominates other welding processes in the maintenance and repair industry, and though flux-cored arc welding is growing in popularity, SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. (
  • The process grants the operator greater control over the weld than competing processes such as shielded metal arc welding and gas metal arc welding , allowing for stronger, higher quality welds. (
  • Examples of welding processes. (
  • Welding is one of the manufacturing processes by which two or more similar or dissimilar materials can be joined permanently by coalescence formation with or without the applications of external pressure, heat or filler material. (
  • I know you will find it helpful because it will provide you with the definitions of most welding and metalworking terms used in the industry as well as the various welding applications, processes, techniques, and methods. (
  • Resistance welding is one of the oldest of the electric welding processes in use by industry today. (
  • In this type of welding acetylene gas and oxygen are mixed in a torch so as to attain the high temperatures … Oxy-Acetylene Welding). (
  • From the above types, Oxy-Acetylene Gas Welding was presented below in a detailed way. (
  • Oxy-Acetylene, Gas Welding Rods The Oxy-Fuel process is considered old-school. (
  • GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminium , magnesium , and copper alloys. (
  • After the discovery of the short pulsed electric arc in 1800 by Humphry Davy and of the continuous electric arc in 1802 by Vasily Petrov, there was little development in electrical welding until Auguste de Méritens developed a carbon arc torch that was patented in 1881. (
  • It affords greater control and improves weld quality by using a nozzle to focus the electric arc, but is largely limited to automated systems, whereas GTAW remains primarily a manual, hand-held method. (
  • When in contact with the metal being welded an electric arc is created at the gap generating high temperatures of up to 6500o F. (
  • The American Welding Society's official term is gas tungsten arc welding (GTAW). (
  • TIG welding is another name for gas tungsten arc welding. (
  • A related process, plasma arc welding , uses a slightly different welding torch to create a more focused welding arc and as a result is often automated. (
  • oxyacetylene welding process is accomplish by proper mix proportion of acetylene and oxygen gases in weld torch, which passed through flame into welding tip. (
  • MIG/MAG welding equipment is composed of a power source providing the welding current, a wire feeder (built-in or separate), a welding torch or gun and a device for shielding gas supply. (
  • Finally, the development of alternating current units made it possible to stabilize the arc and produce high quality aluminium and magnesium welds. (
  • [9] During the 1950s, as the process continued to gain popularity, some users turned to carbon dioxide as an alternative to the more expensive welding atmospheres consisting of argon and helium , but this proved unacceptable for welding aluminium and magnesium because it reduced weld quality, so it is rarely used with GTAW today. (
  • Wire Diameter The wire feed speed for aluminium welding is about twice that of steel welding with the equivalent diameter wire. (
  • Once part of the weld pool, the slag floats to the surface and protects the weld from contamination as it solidifies. (
  • In welding or cutting, the oxygen/acetylene-focused flame is necessary because the heat needs to be concentrated at a small point. (
  • Oxyacetylene welding, commonly referred to as gas welding, is a process which relies on combustion of oxygen and acetylene. (
  • Welding is generally carried out using the neutral flame setting which has equal quantities of oxygen and acetylene. (
  • O The use of oxygen and acetylene as welding gases dates back to the 1890's. (
  • V In oxyfuel gas welding, the proporation of acetylene and oxygen plays a vital role. (
  • Oxy Acetylene welding is a welding process manually, in which the surfaces to be joined, which is warming to melt by a gas flame Oxyacetylene with or without filler metal, where the connection process without emphasis. (
  • A constant-current welding power supply produces electrical energy, which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma . (
  • After blasting and subsequent cleaning, the glass surface was still covered with adhering glass particles. (
  • These particles, cracks, and scratch ‐ like textures could not be removed by cleaning. (
  • In the 1950s, manufacturers introduced iron powder into the flux coating, making it possible to increase the welding speed. (
  • The arc voltage and wire feed rate will determine the filler metal transfer method. (
  • As the name resistance welding implies, it is the resistance of the material to welded, to current flow that causes a localized heating in the part. (
  • Because various types of metals yield different rates of flow, finding the right welding regulator is necessary for control. (
  • It is non-flammable, colorless and is a widely utilized fuel in metal cutting and oxyacetylene welding. (
  • A welding process that involves chemical reaction to produce heat (e.g. (
  • The welding process uses substantial energy to melt the surface of the components to be joined. (
  • A few years later, a direct current , gas-shielded welding process emerged in the aircraft industry for welding magnesium. (
  • When carrying out cored wire welding without a shielding gas, the same power source and wire feed unit are usually used as would be used for welding with shielding gas. (
  • In my opinion the thing which set these welders apart isn''t the metal and isn''t the gas - it is the wire feed and calling them "wire fed welders" or something like that would have been clearer. (
  • Linde developed water-cooled torches that helped prevent overheating when welding with high currents. (
  • To strike the welding arc, a high frequency generator (similar to a Tesla coil ) provides an electric spark . (
  • The weld is made by a coination of heat, pressure and time. (
  • 7/3/2010· Basically welding aluminum without a shielding gas = a bad idea. (
  • [11] In 1953, a new process based on GTAW was developed, called plasma arc welding. (
  • A gas-welding process in which the heat is obtained from the combustion of acetylene and air. (
  • acetylene: A colorless, highly flammable or explosive gas, C 2 H 2 , used for metal welding and cutting and as an illuminant. (

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