Occlusion

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Related to arterial occlusion: venous occlusion

occlusion

[ə′klü·zhən]
(anatomy)
The relationship of the masticatory surfaces of the maxillary teeth to the masticatory surfaces of the mandibular teeth when the jaws are closed.
(computer science)
In computer vision, the obstruction of a view.
(engineering)
The retention of undissolved gas in a solid during solidification.
(medicine)
A closing or shutting up.
(meteorology)
(physics)
Adhesion of gas or liquid on a solid mass, or the trapping of a gas or liquid within a mass.
(physiology)
The deficit in muscular tension when two afferent nerves that share certain motor neurons in the central nervous system are stimulated simultaneously, as compared to the sum of tensions when the two nerves are stimulated separately.

Occlusion

 

the absorption of a substance from a gaseous medium by solids or melts. During occlusion, gases are absorbed by the entire volume of the absorbent rather than by the surface layer. In this sense, occlusion is similar to absorption, which is the dissolution of gases in liquids.

The most common type of occlusion involves the absorption of gases by metals; for example, hydrogen is occluded by metals of Group VIII of the periodic table of elements. At room temperature, one volume of iridium absorbs more than 800 volumes of hydrogen, and one volume of palladium absorbs more than 700 volumes of hydrogen. The occluded gas interacts with the metal to form a solid solution; sometimes a part of the gas combines with the metal to yield other chemical compounds, for example, hydrides and nitrides.


Occlusion

 

(also bite), the relationship between the surfaces of the upper and lower teeth when in contact. The various forms of occlusion are established only when all the permanent teeth are present. With normal occlusion, each upper tooth, except the central incisors and the wisdom teeth, must touch the corresponding bottom tooth and the tooth behind it when the jaws are in contact. The sagittal surface passes between the central incisors of the upper and lower jaws.

There are four types of physiological occlusion. With orthognathous occlusion, the front teeth of the upper jaw cover the corresponding teeth of the lower jaw. Biprognathous occlusion is similar but with a more pronounced slant forward of the upper and lower teeth and of the alveolar processes. With a straight bite, the front teeth close on the edges of the incisors, and with an opisthognathous bite, the front teeth of both upper and lower jaws are inclined backward.

Pathological occlusion, which includes overbite, decreases the chewing efficiency of the teeth. It may be a congenital anomaly of development of the dentomaxillary system or a result of tooth removal or jaw disease or injury.

REFERENCES

Gavrilov, E. I., and I. M. Al’shits. Ortopedicheskaia stomatologiia. Moscow, 1970.
Kurliandskii, V. Iu. Rukovodstvo k prakticheskim zaniatiiam po ortopedicheskoi stomatologii, 3rd ed. Moscow, 1973.

A. I. RYBAKOV

occluded front

occluded frontclick for a larger image
Fronts formed by the merging of cold and warm fronts. If a cold front overtakes a warm front, the result would be an occluded front. Also known as a frontal occlusion or an occlusion. See also front.
References in periodicals archive ?
The Oxy-Hb level recorded at rest was defined as 100%, and the minimum Oxy-Hb plateau level recorded after 6 minutes' arterial occlusion was defined as 0%.
When outcomes were compared based on the type of arterial occlusion used, the differences between the 26 patients who underwent uterine artery embolization and the 24 patients with no arterial occlusion remained statistically significant, but no significant differences were seen between the 13 who underwent hypogastric balloon inflation and those with no occlusion, Dr.
Which of the following statements about retinal arterial occlusions is FALSE?
About Leg Attack Acute peripheral arterial occlusion (PAO), or "leg attack," is the blocking of arterial blood flow to the lower limbs by a clot.
3) In an earlier survey, Calkins et al identified two strap-type tourniquets that did provide satisfactory arterial occlusion, both employed a ratchet device with a 1.
Their evaluation included a baseline laser Doppler measure of skin perfusion in the left dorsal hand skin for at least 2 minutes; reperfusion was studied after a 1-minute arterial occlusion with an inflated pneumatic wrist cuff.
This can be caused by atherosclerotic vascular disease, tobacco, hypertension, diabetes, high cholesterol, radiation and stress, or traumatic arterial occlusion (pelvic fracture or blunt perineal trauma).
The investigators chose middle cerebral artery stroke because it is the most frequent site of arterial occlusion in patients with a severe stroke of less than 6 hours' duration.
sup][16] Recently, other magnetic resonance techniques, such as True Fast Imaging in Steady State Precession [sup][7] or basiparallel anatomic scanning-MRI [sup][8],[9] were introduced to differentiate arterial occlusion from vertebral hypoplastic variants.
DIFFERENTIAL DIAGNOSIS: Moyamoya syndrome (also termed the moyamoya pattern or phenomenon) is due to numerous conditions that can cause arterial occlusion of the circle of Willis, with resultant collaterals, and appearances reminiscent of moyamoya disease.
3,4) The 3 main categories of vascular involvement are venous occlusion, arterial occlusion, and arterial saccular or fusiform aneurysm formation.