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 stuff 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 much body sites) upon a filter having pores of uniform size less than the cellular material to be concentrated; this is followed by fixation and staining, generally 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 arm and with the superior vena cava on the another; used in physiologic research of the heart and circulation.