Abstract
In this division, we have reported in the past, on the development of equipment to measure the 6degree freedom of the low jaw movement.
We have now developed a new system which is lighter and is able to be applied better clinically to infants and which enables the measurement of the upper and lower jaw movement. The properties and reproducibility in measurements were investigated to obtain the following conclusions.
1. A new instrument to measure the upper and lower jaw movement using magnetism has been developed by improving the conventional instrument for measuring the 6 degree freedom of the lower jaw movement using magnetism.
2. The S. E. in measurement for the vertical move was 0.15 mm in average for the 1.5 cm vertical move, and 0.29 mm in average for the 2.5 cm vertical move.
3. The S. E. in measurement for the horizontal move was 0.14 mm in average for the 1.5 cm move, and 0.28 mm for the 2.5 cm move.
4. The maximum individual C. V. in the maximum aperture, which is said to be relatively reproducible in the living body, is 4.1 mm in average, so the reference surface decision method is considered to be relatively reproducible.
5. There is a reproducibility in measurement with this instrument and it is considered to be possible to compare the measured values with those of other people and compare the yearly changes in measured values.
