The average amount of disocclusion on working side during lateral movement of subjects with normal dentition and free of TMD, was 0.41±0.27mm, measured on the study models mounted on a semi-adjustable articulator, using a leaf gauge.
The frequency of occurence for canine guided occlusion (mutually protected occlusion) is larger than that for group functioned occlusion by about 10 times (50 samples vs 4 samples) .
The fact that there are distinctly significant difference between the average amounts of disocclusion during the protrusive movement and on the nonworking side lateral movement and the one on the working side lateral movement, indicates that the proper amounts of disocclusion is necessary for establishing sound occlusion.

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Placing the rubber band around a maxillary study model with mounting plate, and using its edge as a reference, mesio-distal positions of mesio-buccal molar cusp tips were meaured in mm using a scale. Comparing the results with the anatomical data reported by Sekikawa et al, fairly good coincidence was obtained.

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The amount of disocclusion on nonworking side during lateral movement of the mandible was measured on the study model, using a leaf gauge, after removing canine teeth from the study models. The results showed that the average amount of disocclusin without canine teeth on nonworking side during lateral movement, is 0.82±0.36mm, decreasing only 35% by removing canine teeth. Therefore, it has been shown that disocclusion appears normal on nonworking side, even if canine teeth are removed.

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The vertical positions of teeth on mandibular tooth arrangement were measured by newly devised clinical method. Combining the results with the measured data of mesio-distal positions of teeth, the average radius of Spee's curve was obtained by drawing in actual dimensions. As the result, it was shown that the circular arc with the radius of 180 mm matches well with the curve drawn through incisal point, second premolar and second molar, and the circular arc with the radius of 220mm matches well with the curve drawn through incisal point, second premolar and first molar. By this study, the average radius of Spee's curve among Japanese was first measured.

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Mathematical expressions for computing cusp path inclinations from guiding factors of condylar and incisal paths were derived, based upon the kinematic formulae for mandibular movement. In addition to expressions for computing cusp path inclinations, expressions for horizontal cusp path angle were also derived.

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4 methods of occlusal registration, that is the chin guide technique, the bilateral technique, the three-finger technique and the leaf-gauge technique were compared with use of a portable electromyograph EM-II manufactured by Myotronics, USA. The result showed that the wave form obtained in the leaf-gauge technique was similar to that obtained at the inter-cuspal position, and that the leaf-gauge technique is the superior method of the centric bite registration to the chin guide technique, the bilateral technique and the three-finger technique. The chin guide technique showed the most posterior position of the condylar head, while both the bilateral technique and the three-finger technique showed the most superior-anterior position of the condylar head, resulting in disturbed wave forms of E.M.G.

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