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Dental Amalgam
In dentistry, amalgam is an alloy of mercury used to fill teeth cavities. It is made by mixing a combination of liquid mercury and particles of solid metals such as silver, copper or tin. The amalgam is mixed by the dentist just before use. It remains soft for a short while after mixing, which facilitates it being snugly packed into the cavity and shaped before it sets hard. Dental amalgams were first documented in a Tang dynasty medical text written by Su Gong (苏恭) in 659, and appeared in Germany in 1528. In the 1800s, amalgam became the dental restorative material of choice due to its low cost, ease of application, strength, and durability. History of use There are, according to Geir Bjørklund, indications that dental amalgam was used in the first part of the Tang dynasty in China (AD 618–907), and in Germany by Strockerus in about 1528. Evidence of a dental amalgam first appears in the Tang dynasty medical text ''Xinxiu bencao'' (新修本草) written by Su Gong ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filling
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Filling may refer to: * a food mixture used for stuffing * Frosting used between layers of a cake * Dental restoration * Symplectic filling, a kind of cobordism in mathematics * Part of the leather crusting process See also * Fill (other) Fill may refer to: * Fill dirt, soil added to an area ** Fill (archaeology), material accumulated in a feature such as a ditch or pit ** Material used in cut and fill to elevate a surface * Fill character, added in data transmission to consu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (element)
Mercury is a chemical element; it has Symbol (chemistry), symbol Hg and atomic number 80. It is commonly known as quicksilver. A Heavy metal element, heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is obtained by Mill (grinding), grinding natural cinnabar or synthetic mercuric sulfide. Exposure to mercury and mercury-containing organic compounds is toxic to the nervous system, immune system and kidneys of humans and other animals; mercury poisoning can result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury) either directly or through mechanisms of biomagnification. Mercu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New England
New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the Canadian provinces of New Brunswick to the northeast and Quebec to the north. The Gulf of Maine and Atlantic Ocean are to the east and southeast, and Long Island Sound is to the southwest. Boston is New England's largest city and the capital of Massachusetts. Greater Boston, comprising the Boston–Worcester–Providence Combined Statistical Area, houses more than half of New England's population; this area includes Worcester, Massachusetts, the second-largest city in New England; Manchester, New Hampshire, the largest city in New Hampshire; and Providence, Rhode Island, the capital of and largest city in Rhode Island. In 1620, the Pilgrims (Plymouth Colony), Pilgrims established Plymouth Colony, the second successful settlement in Briti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minamata Convention On Mercury
The Minamata Convention on Mercury is an international treaty designed to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. The convention was a result of three years of meeting and negotiating, after which the text of the convention was approved by delegates representing close to 140 countries on 19 January 2013 in Geneva and adopted and signed later that year on 10 October 2013 at a diplomatic conference held in Kumamoto, Japan. The convention is named after the Japanese city Minamata. This naming is of symbolic importance as the city went through a devastating incident of mercury poisoning. It is expected that over the next few decades, this international agreement will enhance the reduction of mercury pollution from the targeted activities responsible for the major release of mercury to the immediate environment. The objective of the Minamata Convention is to protect the human health and the environment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caries
Tooth decay, also known as caries,The word 'caries' is a mass noun, and is not a plural of 'carie'.'' is the breakdown of teeth due to acids produced by bacteria. The resulting cavities may be a number of different colors, from yellow to black. Symptoms may include pain and difficulty eating. Complications may include inflammation of the tissue around the tooth, tooth loss and infection or abscess formation. Tooth regeneration is an ongoing stem cell–based field of study that aims to find methods to reverse the effects of decay; current methods are based on easing symptoms. The cause of cavities is acid from bacteria dissolving the hard tissues of the teeth ( enamel, dentin and cementum). The acid is produced by the bacteria when they break down food debris or sugar on the tooth surface. Simple sugars in food are these bacteria's primary energy source and thus a diet high in simple sugar is a risk factor. If mineral breakdown is greater than buildup from sources such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commonly Used Terms Of Relationship And Comparison In Dentistry
This is a list of definitions of commonly used terms of location and direction in dentistry. This set of terms provides orientation within the oral cavity, much as anatomical terms of location provide orientation throughout the body. Terms Combining of terms Most of the principal terms can be combined using their corresponding combining forms (such as ''mesio-'' for ''mesial'' and ''disto-'' for ''distal''). They provide names for directions (vectors) and axes; for example, the coronoapical axis is the long axis of a tooth. Such combining yields terms such as those in the following list. The abbreviations should be used only in restricted contexts, where they are explicitly defined and help avoid extensive repetition (for example, a journal article that uses the term "mesiodistal" dozens of times might use the abbreviation "MD"). The abbreviations are ambiguous: (1) they are not spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casa Pia
The Casa Pia is a Portuguese institution founded by Maria I, known as ''A Pia'' ("Mary the Pious"), and organized by Police Intendant Pina Manique in 1780, following the social disarray of the 1755 Lisbon earthquake. For almost three centuries, thousands of young boys and girls were raised by Casa Pia, including many public personalities, called casapianos. Casa Pia is Portugal's largest educational institution dedicated to helping youngsters in risk of social exclusion or without parental support. The organisation is composed of ten schools and enrolls approximately 4700 students. In addition to standard schooling, the organisation also provides boarding for children in need. It strives to enable these youngsters to become healthy and successful members of society, by developing intellectual, manual, and physical traits, in an environment promoting spiritual, moral, and religious values. The institution is proud to have had amongst its students many outstanding Portuguese pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methacrylate
Methacrylates are derivatives of methacrylic acid. These derivatives are mainly used to make poly(methyl methacrylate) and related polymers. *Monomers ** Methyl methacrylate ** Ethyl methacrylate ** Butyl methacrylate ** Hydroxyethyl methacrylate ** Glycidyl methacrylate Glycidyl methacrylate (GMA) is an ester of methacrylic acid and glycidol. Containing both an epoxide and an acrylate group, the molecule is bifunctional. It is a common monomer A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecu ... {{set index Carboxylate anions Monomers Methacrylate esters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteriostatic Agent
A bacteriostatic agent or bacteriostat, abbreviated Bstatic, is a biological or chemical agent that stops bacteria from reproducing, while not necessarily killing them otherwise. Depending on their application, bacteriostatic antibiotics, disinfectants, antiseptics and preservatives can be distinguished. When bacteriostatic antimicrobials are used, the duration of therapy must be sufficient to allow host defense mechanisms to eradicate the bacteria. Upon removal of the bacteriostat, the bacteria usually start to grow rapidly. This is in contrast to bactericides, which kill bacteria. Bacteriostats are often used in plastics to prevent growth of bacteria on surfaces. Bacteriostats commonly used in laboratory work include sodium azide (which is acutely toxic) and thiomersal. __TOC__ Bacteriostatic antibiotics Bacteriostatic antibiotics limit the growth of bacteria by interfering with bacterial protein production, DNA replication, or other aspects of bacterial cellular metabolism. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Resin
Dental composite resins (better referred to as "resin-based composites" or simply "filled resins") are dental cements made of synthetic resins. Synthetic resins evolved as restorative materials since they were insoluble, of good tooth-like appearance, insensitive to dehydration, easy to manipulate and inexpensive. Composite resins are most commonly composed of Bis-GMA and other dimethacrylate monomers (TEGMA, UDMA, HDDMA), a filler material such as silica and in most applications, a photoinitiator. Dimethylglyoxime is also commonly added to achieve certain physical properties such as flow-ability. Further tailoring of physical properties is achieved by formulating unique concentrations of each constituent. Many studies have compared the lesser longevity of resin-based composite restorations to the longevity of silver- mercury amalgam restorations. Depending on the skill of the dentist, patient characteristics and the type and location of damage, composite restorations can hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creep (deformation)
In materials science, creep (sometimes called cold flow) is the tendency of a solid material to undergo slow deformation while subject to persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material. Creep is more severe in materials that are subjected to heat for long periods and generally increases as they near their melting point. The rate of deformation is a function of the material's properties, exposure time, exposure temperature and the applied structural load. Depending on the magnitude of the applied stress and its duration, the deformation may become so large that a component can no longer perform its function – for example creep of a turbine blade could cause the blade to contact the casing, resulting in the failure of the blade. Creep is usually of concern to engineers and metallurgists when evaluating components that operate under high stresses or high temperatures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trituration
Trituration (Latin, ''grinding'') is the name of several different methods used to process materials. In one sense, it is a form of comminution (reducing the particle size of a substance). In another sense, it is the production of a homogeneous powdered material by mixing and grinding component materials thoroughly. For example, a dental amalgam is formed by combining particles of a metal, usually gold or silver, with mercury. *In organic chemistry, trituration is a process used to purify crude chemical compounds containing soluble impurities. A solvent is chosen in which the desired product is insoluble and the undesired by-products are very soluble or vice versa. For example, when the impurities are soluble and the desired product is not, the crude material is washed with the solvent and filtered, leaving the purified product in solid form and any impurities in solution. If mixed solvents are used, target compound and impurities are first dissolved in small amount of solvent, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
