Curve of Spee

The curve of Spee ( " Spee curve " or " sagittal Okklusionskurve " ) is the arc that connects the incisal edges and cusps of the upper teeth together and back touches the Condylon. The center is located in the center of the orbit. It was named after the Kiel anatomists Ferdinand Graf Spee ( 1855-1937 ).

The arc- shaped arrangement of the teeth by the curve of Spee (compensation curve) when anatomically modern humans (Homo sapiens ) is a space-saving arrangement mesiodistally. It causes a different profile and is associated with a different direction of pull of the masticatory muscles than in primates pines. The primate jaw and the jaw of fossil hominids are by the horizontal juxtaposition of the teeth, for example, is significantly longer ( G.-H. Schumacher 1997 DGKFO 1963).

Evolution aspects

The theory of evolution as specified by the German Orthodontic Society, DGKFO, 1963, the official anatomy ( Schumacher ):

Functional Significance

The principle of the curve of Spee is to bring the chewing surfaces of the located in the main field of force of the masticatory muscles molars in a favorable position for the function. This is achieved when they are approximately perpendicular to the main direction of the masticatory muscles, thus the molar roots are loaded predominantly längsachsig ( G.-H. Schumacher 1997, The evolution of teeth). Investigations in 1961 by G.-H. Schumacher showed that the muscles of mastication temporalis, masseter and lateral pterygoid not perpendicular to the constructed, artificial occlusal plane straight but oblique effect (also G.-H. Schumacher 1997).

The curvature of the Spee curve thus enables after G.-H. Schumacher, that the muscles of mastication except adduction can still develop protraction - retraction and Lateralzugkomponenten. A straightening of the Kaukurve by orthodontic measures about which cause an even bite plane would destroy the entire masticatory system of modern man, the functional balance and tread design.

Source

G -H. Schumacher: The Functional Anatomy of the orofacial system, Hüthig Verlag, Heidelberg, 1985