| extension form | The extension of the cavity preparation outline form to include areas of incipient carious lesions; this extension provides a dental restoration with margins that are self-cleansing or easily cleaned. (05 Mar 2000) |
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| Buck's extension | Apparatus for applying longitudinal skin traction on the leg through contact between the skin and adhesive tape; friction between the tape and skin permits application of force, which is applied through a cord over a pulley, suspending a weight; elevation of the foot of the bed allows the body to act as a counterweight. Synonym: Buck's traction. (05 Mar 2000) |
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| paraplegia in extension | Paralysis of the legs, maintained in an extended position by hypertonic extensor muscles. (05 Mar 2000) |
| ridge extension | An intraoral surgical operation for deepening the labial, buccal, and/or lingual sulci; it is performed to increase the intraoral height of the alveolar ridge in order to assist denture retention. (05 Mar 2000) |
| crossed extension reflex | Extension of the contralateral hind limb when the paw of an animal is painfully stimulated or the central cut end of an afferent nerve, e.g., the peroneal, is stimulated; sometimes occurs in humans upon tapping the skin. (05 Mar 2000) |
| primer extension | A technique for determining the 5'-untranslated region of a specific mRNA molecule. Uses an oligonucleotide complementary to the known RNA sequence as a primer for cDNA synthesis via reverse transcriptase. (05 Mar 2000) |
| skeletal extension | Traction pull on a bone structure mediated through pin or wire inserted into the bone to reduce a fracture of long bones. Synonym: skeletal extension. (05 Mar 2000) |
| nail extension | An obsolete method of extension, by a weight on a nail or pin in the distal fragment of a fracture. (05 Mar 2000) |
| extension | 1. <orthopaedics> The movement by which the two elements of any jointed part are drawn away from each other. 2. <anatomy> A movement which brings the members of a limb into or toward a straight relation. Origin: L. Extensio (18 Nov 1997) |
| extension bridge | A fixed partial bridge denture in which the pontic is retained only on one side by an abutment tooth. Synonym: extension bridge. (05 Mar 2000) |
| a-form DNA | <molecular biology> One of several forms that can be assumed by a double helix. A-DNA is stable in dehydrated conditions. This form is less common than the dominant form found under physiological conditions -- beta-DNA. This form is also assumed by DNA-RNA hybrid helices and by regions of double-stranded RNA. It is a right-handed helix and is a more compact form than beta-DNA. (09 Oct 1997) |
| boat form | The less stable of two conformations assumed by 6-membered cyclic sugars (pyranoses) or cyclohexane derivatives, as opposed to chair form. See: Haworth conformational formulas of cyclic sugars. (05 Mar 2000) |
| cavity preparation form | The configuration or shape of a cavity preparation. (05 Mar 2000) |
| replicative form | An intermediate stage in the replication of either DNA or RNA viral genomes that is usually double stranded, the altered, double-stranded form to which single-stranded coliphage DNA is converted after infection of a susceptible bacterium, formation of the complementary ("minus") strand being mediated by enzymes that were present in the bacterium before entrance of the viral ("plus") strand. (05 Mar 2000) |
| resistance form | The shape given to a cavity preparation that enables the dental restoration to withstand masticatory forces. (05 Mar 2000) |
| retention form | The shape of a cavity preparation that prevents displacement of the dental restoration by lateral or tipping forces as well as masticatory forces. (05 Mar 2000) |