The amounts of disocclusion on working side during lateral movement were measured under the condition without canine teeth by removing anterior segment from the study model mounted on a semi-adjustable articulator. The leaf gauge was used for the measurement. The average amount of disoclusion for molars was 0.16±0.16mm, which is about 40% of the value under the condition with canine teeth.
Comparing this result with the data obtained on nonworking side, it was shown that the difference between the amounts of disocclusion with and without canine teeth is almost equal over all molar teeth arrangement including both working and nonworking sides. This fact shows the increment of the angle of hinge rotation of the mandible affects almost uniformly bucco-linqually and mesio-distally during lateral movement. This result confirms the prospect based upon Hobo and Takayama's theory of the mandibular movement.

抄録全体を表示

Using leaf gauge, the interocclusal distances of the upper and lower study models mounted on a semiadjustable articulator in maximum intercuspation was measured. The average interocclusal distance was 0.05±0.10mm (S.D.) for molars. Providing the diameter of man's hair is about 30 microns, a hair will pass through between upper and lower teeth in maximum intercuspation.

抄録全体を表示

Canine path length and lateral condylar path length during lateral movement were measures on the mounted diagnostic casts with silicone impression material and modeling compound.
The results of the measurments for twenty patients showed that the canine path length was 4.1±1.1 mm and condylar path length was 3.7±1.1mm. The correlation coefficient between two length was 0.77 (p=0.01) . According to this results, the amounts of vertical and horizontal overlaps of canines were estimated as 2.1±0.6mm and 2.9±0.8mm, respectively.

抄録全体を表示

Distannces between mesio-buccal cusp tips of the right and left molars were measured using scale, on a mandibular study model. Comparing this data with the anatomical data reported by Sekikawa et al, good coincidence was obtained.

抄録全体を表示

Mathematical expressions for computing cusp path inclinations from adjusted values of condylar path and incisal guide table on an articulator, 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.

抄録全体を表示