|
Fluoride Toothpaste
Toothpaste is a paste or gel dentifrice that is used with a toothbrush to clean and maintain the aesthetics of teeth. Toothpaste is used to promote oral hygiene: it is an abrasive that aids in removing dental plaque and food from the teeth, assists in suppressing halitosis, and delivers active ingredients (most commonly fluoride) to help prevent tooth decay (dental caries) and gum disease (gingivitis).American Dental Association Description of Toothpaste Due to variations in composition and fluoride content, not all toothpastes are equally effective in maintaining oral health. The decline of tooth decay during the 20th century has been attributed to the introduction and regular use of fluoride-containing toothpastes worldwide. Large amounts of swallowed toothpaste can be poisonous. Common colors for toothpaste include white (sometimes with colored stripes or green tint) and blue. History Early toothpastes Since 5000 BCE, the Egyptians made a tooth powder, which consisted of powd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Al-Andalus
Al-Andalus () was the Muslim-ruled area of the Iberian Peninsula. The name refers to the different Muslim states that controlled these territories at various times between 711 and 1492. At its greatest geographical extent, it occupied most of the peninsula as well as Septimania under Umayyad rule. These boundaries changed through a series of conquests Western historiography has traditionally characterized as the ''Reconquista'',"Para los autores árabes medievales, el término Al-Andalus designa la totalidad de las zonas conquistadas – siquiera temporalmente – por tropas arabo-musulmanas en territorios actualmente pertenecientes a Portugal, España y Francia" ("For medieval Arab authors, Al-Andalus designated all the conquered areas – even temporarily – by Arab-Muslim troops in territories now belonging to Spain, Portugal and France"), García de Cortázar, José Ángel. ''V Semana de Estudios Medievales: Nájera, 1 al 5 de agosto de 1994'', Gobie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeolite
Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. The term was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material ''zeolite'', from the Greek , meaning "to boil" and , meaning "stone". Zeolites occur naturally, but are also produced industrially on a large scale. , 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure that is obtained is examined by the International Zeolite Association Structure Commission (IZA-SC) and receives a three-letter designation. Character ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a synthetic product. Examples include fused quartz, fumed silica, opal, and aerogels. It is used in structural materials, microelectronics, and as components in the food and pharmaceutical industries. All forms are white or colorless, although impure samples can be colored. Silicon dioxide is a common fundamental constituent of glass. Structure In the majority of silicon dioxides, the silicon atom shows Tetrahedral molecular geometry, tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Hydrogen Phosphate
Dicalcium phosphate is the calcium phosphate with the formula CaHPO4 and its dihydrate. The "di" prefix in the common name arises because the formation of the HPO42– anion involves the removal of two protons from phosphoric acid, H3PO4. It is also known as dibasic calcium phosphate or calcium monohydrogen phosphate. Dicalcium phosphate is used as a food additive, and it is found in some toothpastes as a polishing agent and biomaterial. Preparation Dibasic calcium phosphate is produced by neutralizing calcium hydroxide with phosphoric acid, precipitating the dihydrate as a solid. At 60 °C the anhydrous form is precipitated: To prevent degradation that would form hydroxyapatite, sodium pyrophosphate or magnesium phosphate tribasic, trimagnesium phosphate octahydrate are added when, for example, dibasic calcium phosphate dihydrate is to be used as a polishing agent in toothpaste. In a continuous process calcium chloride, CaCl2 can be treated with diammonium phosphate, (NH4) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Bicarbonate
Sodium bicarbonate ( IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cation ( Na+) and a bicarbonate anion (). Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda ( sodium carbonate). The natural mineral form is nahcolite, although it is more commonly found as a component of the mineral trona. As it has long been known and widely used, the salt has many different names such as baking soda, bread soda, cooking soda, brewing soda and bicarbonate of soda and can often be found near baking powder in stores. The term ''baking soda'' is more common in the United States, while ''bicarbonate of soda'' is more common in Australia, the United Kingdom, and New Zealand. Abbreviated colloquial forms such as '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Carbonate
Magnesium carbonate, (archaic name magnesia alba), is an inorganic salt that is a colourless or white solid. Several hydrated and Base (chemistry), basic forms of magnesium carbonate also exist as minerals. Forms The most common magnesium carbonate forms are the anhydrous salt called magnesite (), and the di, tri, and pentahydrates known as barringtonite (), nesquehonite (), and lansfordite (), respectively. Some basic forms such as artinite (), hydromagnesite (), and dypingite () also occur as minerals. All of those minerals are colourless or white. Magnesite consists of colourless or white trigonal crystals. The anhydrous salt is practically insoluble in water, acetone, and ammonia. All forms of magnesium carbonate react with acids. Magnesite crystallizes in the calcite structure wherein magnesium, is Coordination geometry#Crystallography usage, surrounded by six oxygen atoms. The dihydrate has a triclinic structure, while the trihydrate has a monoclinic structure. Refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Carbonate
Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls. Materials containing much calcium carbonate or resembling it are described as calcareous. Calcium carbonate is the active ingredient in agricultural lime and is produced when calcium ions in hard water react with carbonate ions to form limescale. It has medical use as a calcium supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues. Chemistry Calcium carbonate shares the typical properties of other carbonates. Notably, it: *reacts with acids, releasing carbonic acid which quickly disintegrates into carbon dioxide and water: : *releases carbon dioxide upon heating, called a thermal decomposition reaction, or calcination (to above 840 °C in the case of ), t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminum Hydroxide
Aluminium hydroxide, , is found as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic and acidic properties. Closely related are aluminium oxide hydroxide, AlO(OH), and aluminium oxide or alumina (), the latter of which is also amphoteric. These compounds together are the major components of the aluminium ore bauxite. Aluminium hydroxide also forms a gelatinous precipitate in water. Structure is built up of double layers of hydroxyl groups with aluminium ions occupying two-thirds of the octahedral holes between the two layers. Four polymorphs are recognized. All feature layers of octahedral aluminium hydroxide units, with hydrogen bonds between the layers. The polymorphs differ in terms of the stacking of the layers. All forms of crystals are hexagonal : * gibbsite is also known as γ- or α- * bayerite is also known as α- or ''β-alu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calculus (dental)
In dentistry, calculus or tartar is a form of hardened dental plaque. It is caused by precipitation of minerals from saliva and Gingival sulcus, gingival crevicular fluid (GCF) in plaque on the teeth. This process of precipitation kills the bacterial cells within dental plaque, but the rough and hardened surface that is formed provides an ideal surface for further plaque formation. This leads to calculus buildup, which compromises the health of the gingiva (gums). Calculus can form both along the gumline, where it is referred to as supragingival (), and within the narrow Sulcus (morphology), sulcus that exists between the teeth and the gingiva, where it is referred to as subgingival (). Calculus formation is associated with a number of clinical manifestations, including halitosis, bad breath, receding gums and Chronic (medicine), chronically inflamed gingiva. Brushing and flossing can remove plaque from which calculus forms; however, once formed, calculus is too hard (firmly att ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hiraga Gennai
was a Japanese polymath and ''rōnin'' of the Edo period. He was a pharmacologist, student of ''Rangaku'', author, painter and inventor well known for his '' Erekiteru'' (electrostatic generator), ''Kandankei'' (thermometer) and ''Kakanpu'' (asbestos cloth). Gennai composed several works of literature, including the fictional satires ''Fūryū Shidōken den'' (1763), the ''Nenashigusa'' (1763), and the ''Nenashigusa kohen'' (1768), and the satirical essays ''On Farting'' and ''A Lousy Journey of Love''. He also authored two guidebooks on the male prostitutes of Japan, the ''Kiku no en'' (1764) and the ''San no asa'' (1768). His birth name was Shiraishi Kunitomo, but he later used numerous pen names, including , (his principal literary pen name), and . He is best known by the name Hiraga Gennai. Biography Family history Hiraga Gennai was born in 1729 in the village of Shidoura, Sanuki Province (part of the modern city of Sanuki, Kagawa). He was the third son of Shiroish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edo Period
The , also known as the , is the period between 1600 or 1603 and 1868 in the history of Japan, when the country was under the rule of the Tokugawa shogunate and some 300 regional ''daimyo'', or feudal lords. Emerging from the chaos of the Sengoku period, the Edo period was characterized by prolonged peace and stability, urbanization and economic growth, strict social order, Isolationism, isolationist foreign policies, and popular enjoyment of Japanese art, arts and Culture of Japan, culture. In 1600, Tokugawa Ieyasu prevailed at the Battle of Sekigahara and established hegemony over most of Japan, and in 1603 was given the title ''shogun'' by Emperor Go-Yōzei. Ieyasu resigned two years later in favor of his son Tokugawa Hidetada, Hidetada, but maintained power, and defeated the primary rival to his authority, Toyotomi Hideyori, at the Siege of Osaka in 1615 before his death the next year. Peace generally prevailed from this point on, making samurai largely redundant. Tokugawa sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
