| sample, random | A group selected randomly, solely by chance. (12 Dec 1998) |
|---|---|
| sample size | The number of units (persons, animals, patients, specified circumstances, etc.) in a population to be studied. The sample size should be big enough to have a high likelihood of detecting a true difference between two groups. (12 Dec 1998) |
| stratified sample | A subset of a total population, defined by some objective criterion such as age or occupation, is sampled. (05 Mar 2000) |
| end-tidal sample | A sample of the last gas expired in a normal expiration, ideally consisting only of alveolar gas. (05 Mar 2000) |
| cavity preparation | Removal of dental caries and surgical preparation of the remaining tooth structure to receive a dental restoration, the final form of an excavation in a tooth resulting from such preparation. Corrosion preparation, a preparation in which the hollow parts such as ducts, vessels, or alveoli of the lung are filled with a substance that hardens and persists after dissolving the tissues by digestion. Cytologic filter preparation, a cytologic specimen made by depositing a watery sample (obtained by a variety of methods from many body sites) upon a filter having pores of uniform size smaller than the cellular material to be concentrated; this is followed by fixation and staining, usually with 95% ethyl alcohol and Papanicolaou stain. Heart-lung preparation, an animal preparation in which blood (rendered incoagulable) circulates through the heart and lungs and through an artificial system of vessels representing the systemic circulation; the latter is connected with the divided aorta on the one hand and with the superior vena cava on the other; used in physiologic studies of the heart and circulation. (05 Mar 2000) |
| cavity preparation base | <dentistry> A layer of dental cement, sometimes medicated, that is placed in the deep portion of a cavity preparation to protect the pulp, reduce the bulk of a metallic restoration, or eliminate undercuts. Synonym: cavity preparation base. (05 Mar 2000) |
| cavity preparation form | The configuration or shape of a cavity preparation. (05 Mar 2000) |
| root canal preparation | Preparatory activities in root canal therapy by partial or complete extirpation of diseased pulp, cleaning and sterilization of the empty canal, enlarging and shaping the canal to receive the sealing material. The cavity may be prepared by mechanical, sonic, chemical, or other means. (12 Dec 1998) |
| preparation | 1. <pharmacology> A medicine made ready for use. 2. <anatomy, pathology> A specimen made ready and preserved for study. Origin: L. Praeparatio (18 Nov 1997) |
| histocytological preparation techniques | Methods of preparing cells or tissues for examination and study of their origin, structure, function, or pathology. The methods include preservation, fixation, sectioning, staining, replica, or other technique to allow for viewing using a microscope. (12 Dec 1998) |
| site preparation | Various treatments applied to a harvested area to promote regeneration of the site. (05 Dec 1998) |
| dental cavity preparation | <dentistry> An operation in which carious material is removed from teeth and biomechanically correct forms are established in the teeth to receive and retain restorations. A constant requirement is provision for prevention of failure of the restoration through recurrence of decay or inadequate resistance to applied stresses. (boucher's clinical dental terminology, 4th ed, p239-40) (12 Dec 1998) |
| tooth preparation | Procedures carried out with regard to the teeth or tooth structures preparatory to specified dental therapeutic and surgical measures. (12 Dec 1998) |
| tooth preparation, prosthodontic | The selected form given to a natural tooth when it is reduced by instrumentation to receive a prosthesis (e.g., artificial crown or a retainer for a fixed or removable prosthesis). The selection of the form is guided by clinical circumstances and physical properties of the materials that make up the prosthesis. (boucher's clinical dental terminology, 4th ed, p239) (12 Dec 1998) |