1. That portion of a tooth that lies between the survey line (height of contour) and the gingivae. 2. The contour of a cross-section of a residual ridge or dental arch which would prevent the insertion of a denture. 3. The contour of a flasking stone which interlocks in such a way as to prevent the separation of the parts.
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un·der·cut 'ən-dər-.kət n the part of a tooth lying between the gum and the points of maximum outward bulge on the tooth's surfaces
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un·der·cut (unґdər-kət) 1. the portion of a tooth that lies between the survey line (height of contour) and the gingivae. 2. the contour of a cross-section of a residual ridge or dental arch which would prevent the insertion of a denture. 3. the contour of flasking stone which interlocks in such a way as to prevent the separation of the parts. 4. a depressed or intaglio irregularity in the wall of a prepared tooth that prevents the ready withdrawal and seating of a wax pattern and the metal alloy casting.Medical dictionary. 2011.