Megallium is a trademark for an alloy of 60% cobalt, 20% chromium, 5% molybdenum, and traces of other substances. The alloy is used in dentistry because of its light weight, resistance to corrosion and hypo-allergenic (nickel free) properties. Megallium was developed by John Leonard Attenborough for Attenborough Dental Laboratories in 1951.
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Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). They have similar chemical properties, but palladium has the lowest melting point and is the least dense of them.
Titanium is a chemical element with the symbol Ti and atomic number 22. Its atomic weight is 47.867 measured in daltons. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine.
Sir David Frederick Attenborough is an English broadcaster and natural historian. He is best known for writing and presenting, in conjunction with the BBC Natural History Unit, the nine natural history documentary series forming the Life collection that together constitute a comprehensive survey of animal and plant life on Earth. He is a former senior manager at the BBC, having served as controller of BBC Two and director of programming for BBC Television in the 1960s and 1970s. He is the only person to have won BAFTAs for programmes in each of black and white, colour, HD, 3D and 4K.
Nichrome is a family of alloys of nickel, chromium, and often iron commonly used as resistance wire, heating elements in things like toasters and space heaters, in some dental restorations (fillings) and in a few other applications.
Phosphor bronze is a member of the family of copper alloys. It is composed of copper that is alloyed with 0.5–11% of tin and 0.01–0.35% phosphorus, and may contain other elements to confer specific properties. Alloyed tin increases the corrosion resistance and strength of copper, while phosphorus increases its wear resistance and stiffness.
Dental restoration, dental fillings, or simply fillings, are treatments used to restore the function, integrity, and morphology of missing tooth structure resulting from caries or external trauma as well as to the replacement of such structure supported by dental implants. They are of two broad types—direct and indirect—and are further classified by location and size. A root canal filling, for example, is a restorative technique used to fill the space where the dental pulp normally resides.
In dentistry, a crown most commonly refers to a dental cap, a type of dental restoration which completely caps or encircles a tooth or dental implant. A crown may be needed when a large cavity threatens the health of a tooth. A crown is typically bonded to the tooth by dental cement. They can be made from many materials, which are usually fabricated using indirect methods. Crowns are used to improve the strength or appearance of teeth and to halt deterioration. While beneficial to dental health, the procedure and materials can be costly.
Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness. They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures. However, the high cost of both raw materials and processing limit their use to military applications, aircraft, spacecraft, bicycles, medical devices, jewelry, highly stressed components such as connecting rods on expensive sports cars and some premium sports equipment and consumer electronics.
Aluminium bronze is a type of bronze in which aluminium is the main alloying metal added to copper, in contrast to standard bronze or brass. A variety of aluminium bronzes of differing compositions have found industrial use, with most ranging from 5% to 11% aluminium by weight, the remaining mass being copper; other alloying agents such as iron, nickel, manganese, and silicon are also sometimes added to aluminium bronzes.
An archwire in orthodontics is a wire conforming to the alveolar or dental arch that can be used with dental braces as a source of force in correcting irregularities in the position of the teeth. An archwire can also be used to maintain existing dental positions; in this case it has a retentive purpose.
Michael John Attenborough is an English theatre director.
Gold teeth are a form of dental prosthesis where the visible part of a tooth is replaced or capped with a prosthetic molded from gold. Their main use in modern times is as a status symbol.
Frederick Levi Attenborough was a British academic and principal of University College, Leicester.
A post and core crown is a type of dental restoration required where there is an inadequate amount of sound tooth tissue remaining to retain a conventional crown. A post is cemented into a prepared root canal, which retains a core restoration, which retains the final crown.
Dental amalgam is a liquid mercury and metal alloy mixture used in dentistry to fill cavities caused by tooth decay. Low-copper amalgam commonly consists of mercury (50%), silver (~22–32%), tin (~14%), zinc (~8%) and other trace metals.
An amalgam is an alloy of mercury with another metal. It may be a liquid, a soft paste or a solid, depending upon the proportion of mercury. These alloys are formed through metallic bonding, with the electrostatic attractive force of the conduction electrons working to bind all the positively charged metal ions together into a crystal lattice structure. Almost all metals can form amalgams with mercury, the notable exceptions being iron, platinum, tungsten, and tantalum. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore. Dentistry has used alloys of mercury with metals such as silver, copper, indium, tin and zinc.
The following is a chronological list of television series and individual programmes where Sir David Attenborough is credited as writer, presenter, narrator or producer. In a career spanning eight decades, Attenborough's name has become synonymous with the natural history programmes produced by the BBC Natural History Unit.
Richard Samuel Attenborough, Baron Attenborough, was an English actor, filmmaker, and entrepreneur. He was the president of the Royal Academy of Dramatic Art (RADA) and the British Academy of Film and Television Arts (BAFTA), as well as the life president of Chelsea FC. He joined the Royal Air Force during the Second World War and served in the film unit, going on several bombing raids over Europe and filming the action from the rear gunner's position. He was the older brother of broadcaster Sir David Attenborough and motor executive John Attenborough. He was married to actress Sheila Sim from 1945 until his death.
Cobalt-chrome or cobalt-chromium (CoCr) is a metal alloy of cobalt and chromium. Cobalt-chrome has a very high specific strength and is commonly used in gas turbines, dental implants, and orthopedic implants.