The curve of Spee in Stone Age man.

The purpose of this research was to test Spee's predictions on a sample of skulls with well-worn occlusions. Thirty-nine Shell Mound Indian skulls with marked attrition of the teeth were x-rayed in the Margolis cephalostat. Following Spee's suggested landmarks, three curves were obtained which included the condyle. A fourth curve was investigated--not using the condyle but based from three landmarks of the occlusal surface. All curves, radii, and centers were generated by a computer using the landmarks digitized from each skull's film. When only the molars and the condyle were used, the length of the radius and the location of the center came closest to Spee's predictions. In most of the sample, however, Spee's inclusion of the incisor along that arc could not be verified. Prosthodontic experiments which might give clues to finishing curves for orthodontic patients are suggested.