| porcelain | <botany> Purslain. A fine translucent or semitransculent kind of earthenware, made first in China and Japan, but now also in Europe and America; called also China, or China ware. "Porcelain, by being pure, is apt to break." (Dryden) Ivory porcelain, porcelain with a surface like ivory, produced by depolishing. See Depolishing. Porcelain clay. See Clay. <zoology> Porcelain crab, a cowry. Origin: F. Porcelaine, It. Porcellana, orig, the porcelain shell, or Venus shell (Cypraea porcellana), from a dim. Fr. L. Porcus pig, probably from the resemblance of the shell in shape to a pig's back. Porcelain was called after this shell, either on account of its smoothness and whiteness, or because it was believed to be made from it. See Pork. Source: Websters Dictionary (01 Mar 1998) |
|---|---|
| porcelain gallbladder | <radiology> Calcium incrustation of gallbladder wall, 0.6-0.8% of cholecystectomy patients, 80% female, 10-20% develop gallbladder carcinoma, 90% associated with gallstones findings: nonfunctioning gallbladder on oral cholecystogram, highly echogenic shadowing curvilinear sturucture in the gallbladder fossa (Differential diagnosis: stone-filled contracted gall bladder), echogenic gallbladder wall with little acoustic shadowing (Differential diagnosis: emphysematous cholecystitis), scattered irregular clumps of echoes with posterior acoustic shadowing (12 Dec 1998) |
| porcelain inlay | A fused porcelain restoration luted in a cavity prepared in a tooth. (05 Mar 2000) |
| dental porcelain | <chemical> A type of porcelain used in dental restorations, either jacket crowns or inlays, artificial teeth, or metal-ceramic crowns. It is essentially a mixture of particles of feldspar and quartz, the feldspar melting first and providing a glass matrix for the quartz. Dental porcelain is produced by mixing ceramic powder (a mixture of quartz, kaolin, pigments, opacifiers, a suitable flux, and other substances) with distilled water. Chemical name: Dental materials and fillings, porcelain (12 Dec 1998) |
| anatomical crown | The portion of a tooth covered with enamel. Synonym: corona dentis, anatomical crown. (05 Mar 2000) |
| artificial crown | A fixed restoration of the major part of the entire coronal part of a natural tooth; usually of gold, porcelain, or acrylic resin. (05 Mar 2000) |
| bell-shaped crown | A crown of a tooth with an exaggerated occlusogingival contour; human deciduous molars typify the bell-shaped crown. (05 Mar 2000) |
| radiate crown | A fan-shaped fibre mass on the white matter of the cerebral cortex, composed of the widely radiating fibres of the internal capsule; a single layer of columnar cells derived from the cumulus oophorus, which anchor on the pellucid zone of the oocyte in a secondary follicle. Synonym: radiate crown. (05 Mar 2000) |
| ciliary crown | The circular figure on the inner surface of the ciliary body, formed by the processes and folds (plicae) taken together. Synonym: ciliary crown, ciliary wreath. (05 Mar 2000) |
| clinical crown | That part of the crown of a tooth visible in the oral cavity. Synonym: corona clinica. (05 Mar 2000) |
| crown | The part of a tree or shrub above the level of the lowest branch. (09 Oct 1997) |
| crown angulation | <dentistry> A tooth movement in which the root of the tooth is tipped forward or backward to correct the angle of the crown. (08 Jan 1998) |
| crown cavity | The space within the crown of a tooth continuous with the root canal. Synonym: cavitas coronalis, cavum coronale. (05 Mar 2000) |
| crown flask | A sectional metal boxlike case in which a sectional mold is made of plaster of Paris or artificial stone for the purpose of compressing and curing dentures or other resinous restorations. Synonym: crown flask. (05 Mar 2000) |
| crown gall | Gall or tumour, found in many dicotyledonous plants, caused by the bacterium Agrobacterium tumefaciens. (18 Nov 1997) |