| dental impression materials | Substances or combinations of substances used for making a negative reproduction or impression of the teeth and oral structures for the purpose of producing restorations, prostheses, and dentures, including elastomeric materials, dental plasters, metallic oxide pastes, hydrocolloids, silicone base materials, polyethers, polysulfides, and duplicating compounds. (12 Dec 1998) |
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| dental impression technique | Procedure of producing an imprint or negative likeness of the teeth and/or edentulous areas. Impressions are made in plastic material which becomes hardened or set while in contact with the tissue. They are later filled with plaster of paris or artificial stone to produce a facsimile of the oral structures present. Impressions may be made of a full complement of teeth, of areas where some teeth have been removed, or in a mouth from which all teeth have been extracted. (12 Dec 1998) |
| denture impression surface | That portion of the surface of a denture which has its contour determined by the impression; it includes the borders of the denture and extends to the polished surface. (05 Mar 2000) |
| direct bone impression | An impression of denuded bone, used in the construction of subperiosteal denture implants. (05 Mar 2000) |
| duodenal impression | A hollow on the visceral surface of the right lobe of the liver alongside the gallbladder, marking the situation of the duodenum. Synonym: impressio duodenalis. (05 Mar 2000) |
| impression | 1. The act of impressing, or the state of being impressed; the communication of a stamp, mold, style, or character, by external force or by influence. 2. <dentistry> The first step in making a model of your teeth. You bite into a container filled with algenate, and the algenate hardens to produce a mold of your teeth. 3. That which is impressed; stamp; mark; indentation; sensible result of an influence exerted from without. "The stamp and clear impression of good sense." (Cowper) "To shelter us from impressions of weather, we must spin, we must weave, we must build." (Barrow) 4. The pressure of the type on the paper, or the result of such pressure, as regards its appearance; as, a heavy impression; a clear, or a poor, impression; also, a single copy as the result of printing, or the whole edition printed at a given time. "Ten impressions which his books have had." (Dryden) Origin: F. Impression, L. Impressio. (27 Oct 1998) |
| impression area | In dentistry, that surface which is recorded in an impression. (05 Mar 2000) |
| impression compound | A thermoplastic material usually composed of gum damar and prepared chalk, used especially for making dental impressions. Synonym: impression compound, modeling composition, modeling compound. (05 Mar 2000) |
| impression for costoclavicular ligament | <anatomy> An irregular pitted area on the inferior surface of the clavicle at its sternal end, giving attachment to the costoclavicular ligament. Synonym: impressio ligamenti costoclavicularis, costal tuberosity, rhomboid impression, tuberositas costalis. (05 Mar 2000) |
| impression material | Any substance or combination of substances used for making a negative reproduction or impression. (05 Mar 2000) |
| oesophageal impression | The marking of the oesophagus on the back of the left lobe of the liver. Synonym: impressio oesophagea. (05 Mar 2000) |
| trigeminal impression | A depression on the anterior surface of the petrous portion of the temporal bone, near the apex, lodging the trigeminal ganglion. Synonym: impressio trigeminalis. (05 Mar 2000) |
| final impression | In dentistry, the impression that is used to make the master cast. (05 Mar 2000) |
| analog-digital conversion | The process of converting analog data such as continually measured voltage to discrete, digital form. (12 Dec 1998) |
| angiography, digital subtraction | A method of delineating blood vessels by subtracting a tissue background image from an image of tissue plus intravascular contrast material that attenuates the X-ray photons. The background image is determined from a digitised image taken a few moments before injection of the contrast material. The resulting angiogram is a high-contrast image of the vessel. This subtraction technique allows extraction of a high-intensity signal from the superimposed background information. The image is thus the result of the differential absorption of X-rays by different tissues. (12 Dec 1998) |