Occlusion


Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Wikipedia.
Related to Occlusion: coronary occlusion, arterial occlusion, Dental 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 ?
With these electronic occlusion glasses, the child learns that the lens will be clear again in just a few seconds so they may be more cooperative with the treatment.
ECG discrimination between right and left circumflex coronary arterial occlusion in patients with acute inferior myocardial infarction: value of old criteria and use of lead aVR.
When bilateral paramedian thalamic infarcts are encountered, occlusion of Percheron is considered as the main diagnosis.
Looking again at the overall outcomes, he and his colleagues noted that 53 of the 63 patients with suspected placenta accreta had an attempted uterine preservation, which failed in 35% of the occlusion patients, compared with 88% of the nonocclusion patients.
A standard 12-lead EKG was recorded at 25 mm/sec twice during control and several times during the occlusion and reperfusion periods.
Other studies have shown that vascular occlusion greatly increases the production of growth hormone despite very light loads.
Balloon occlusion of the IVC was re-established and the remaining thrombus was removed.
4,5) The positive predictive value of CTA for diagnosing intracranial occlusion was 100% in these studies.
Iatrogenic causes areincorrect prosthesis, obturations unadjusted with the occlusion, orthodontic treatments incorrectly coordinated.
One of the research papers reports the results of a randomised clinical trial involving 271 participants with macular edema from central retinal vein occlusion.
CHICAGO -- A technique that combines occlusion coils and alcohol sclerosis is the latest addition to the array of catheter-based approaches available to treat varicose veins.