curve of Spee

curve of Spee

[shpā, spē]

Etymology: Ferdinand Graf von Spee, German embryologist, 1855-1937

the anatomic curvature of the occlusal alignment of the teeth. It begins at the tip of the lower canine, follows the buccal cusps of the natural premolars and molars, and continues to the anterior border of the mandibular ramus.

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curve [kerv]

a line that is not straight, or that describes part of a circle, especially a line representing varying values in a graph.

dose-effect curve (dose-response curve) a graphic representation of the effect caused by an agent (such as a drug or radiation) plotted against the dose, showing the relationship of the effect to changes in the dose.

growth curve the curve obtained by plotting increase in size or numbers against the elapsed time.

oxyhemoglobin dissociation curve a graphic curve representing the normal variation in the amount of oxygen that combines with hemoglobin as a function of the partial pressures of oxygen and carbon dioxide. The curve is said to shift to the right when less than a normal amount of oxygen is taken up by the blood at a given Po₂, and to shift to the left when more than a normal amount is taken up. Factors influencing the shape of the curve include changes in the blood pH, Pco₂, and temperature; the presence of carbon monoxide; alterations in the constituents of the erythrocytes; and certain disease states.

pulse curve sphygmogram.

Spee curve (curve of Spee) the anatomic curvature of the occlusal alignment of teeth, beginning at the tip of the lower canine, following the buccal cusps of the premolars and molars, and continuing to the anterior border of the ramus.

strength-duration curve a graphic representation of the relationship between the intensity of an electric stimulus at the motor point of a muscle and the length of time it must flow to elicit a minimal contraction; see also chronaxie and rheobase. In cardiac pacing it is useful in determining characteristics of a particular pacing electrode and determining the most efficient selection of pacing parameters for an appropriate safety margin.

survival curve a graph of the probability of survival versus time, commonly used to present the results of clinical trials, e.g., a graph of the fraction of patients surviving (until death, relapse, or some other defined endpoint) at each time after a certain therapeutic procedure.

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curve,

n a nonangular deviation from a straight line or surface.

curve, alignment,

n See alignment.

curve, anti-Monson,

n.pr See curve, reverse.

curve, compensating,

n the curvature of alignment of the occlusal surfaces of the teeth that is developed to compensate for the paths of the condyles as the mandible moves from centric to eccentric positions. A means of maintaining posterior tooth contacts on the molar teeth and providing balancing contacts on dentures when the mandible is protruded. Corresponds to the curve of Spee of natural teeth.

curve, dose-effect,

n a curve relating the dose of radiation with the effect produced.

curve, dose-response,

n a graphical representation of the relationship between dosage (x-axis) and degree of response (y-axis); used to determine the effective dose of any given drug.

curve, milled-in,

n See path, milled-in.

curve, Monson

n.pr the curve of occlusion, described by Monson, in which each cusp and incisal edge touch or conform to a segment of the surface of a sphere 8 inches (20 cm) in diameter, with its center in the region of the glabella. See also curve, compensating.

curve of occlusion (occlusal curvature),

n 1. a curved occlusal surface that makes simultaneous contact with the major portion of the incisal and occlusal prominences of the existing teeth.
2. the curve of a dentition on which the occlusal surfaces of the teeth lie. See also curve, reverse.

curve of Spee,

n.pr 1. an anatomic curvature of the occlusal alignment of teeth, beginning at the tip of the mandibular canine, following the buccal cusps of the natural premolars and molars, and continuing to the anterior border of the ramus, as described by von Spee.
2. the curve of the occlusal surfaces of the arches in vertical dimension, brought about by a dipping downward of the mandibular premolars, with a corresponding adjustment of the maxillary premolars.

curve of Wilson,

n.pr the curvature of the cusps, as seen from the front view. The curve in the mandibular arch is concave, whereas the one in the maxillary arch is convex.

curve, reverse,

n a curve of occlusion that is convex upward when viewed in the frontal plane.

curve, sine,

n the wave form of an alternating current, characterized by a rise from zero to maximum positive potential, then descending below zero to its maximum negative value, and then rising to its maximum positive potential, to fall to zero again.

curve, survival,

n a curve obtained by plotting the number or percentage of organisms surviving at a given time against a given dose of radiation. A curve showing the percentage of individuals surviving at different intervals after a particular dosage of radiation.