| orthoclase | <chemical> Common or potash feldspar crystallizing in the monoclinic system and having two cleavages at right angles to each other. See Feldspar. Origin: Ortho- + Gr. To break. Source: Websters Dictionary (01 Mar 1998) |
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| orthoclastic | <chemistry> Breaking in directions at right angles to each other; said of the monoclinic feldspars. Source: Websters Dictionary (01 Mar 1998) |
| orthocrasia | An obsolete term for condition in which there is a normal reaction to drugs, articles of diet, etc. Origin: ortho-+ G. Krasis, a mixing, temperament (05 Mar 2000) |
| orthocytosis | A condition in which all of the cellular elements in the circulating blood are mature forms, irrespective of the proportions of various types and total numbers. Origin: ortho-+ G. Kytos, cell, + -osis, condition (05 Mar 2000) |
| orthodentin | Straight tubed dentin as seen in the teeth of mammals. (05 Mar 2000) |
| orthodeoxia | Fall in arterial blood oxygen upon assuming the upright posture. Usually due to right-to-left cardiac or vascular shunting with a posturally induced fall in left sided pressure permitting a corresponding gradient across the shunt. (05 Mar 2000) |
| orthodiagonal | <chemistry> The diagonal or lateral axis in a monoclinic crystal which is at right angles with the vertical axis. Origin: Ortho- + diagonal. Source: Websters Dictionary (01 Mar 1998) |
| orthodigita | Correction of malformations of fingers or toes. Origin: ortho-+ L. Digitus, finger or toe (05 Mar 2000) |
| orthodome | <chemistry> See the Note under Dome. Origin: Ortho- + dome. Source: Websters Dictionary (01 Mar 1998) |
| orthodontia | <dentistry> Braces. (08 Jan 1998) |
| orthodontic appliance | A mechanism for the application of pressure to the teeth and their supporting tissues to produce changes in the relationship of the teeth and/or the related osseous structures. (05 Mar 2000) |
| orthodontic appliance design | The planning, calculation, and creation of an apparatus for the purpose of correcting the placement or straightening of teeth. (12 Dec 1998) |
| orthodontic appliances | Devices used for influencing tooth position. Orthodontic appliances may be classified as fixed or removable, active or retaining, and intraoral or extraoral. (boucher's clinical dental terminology, 4th ed, p19) (12 Dec 1998) |
| orthodontic appliances, functional | Loose, usually removable intra-oral devices which alter the muscle forces against the teeth and craniofacial skeleton. These are dynamic appliances which depend on altered neuromuscular action to effect bony growth and occlusal development. They are usually used in mixed dentition to treat paediatric malocclusions. (ada, 1992) (12 Dec 1998) |
| orthodontic band | A thin strip of metal closely adapted to the crown of a tooth to which wires may be attached for tooth movement. (05 Mar 2000) |