Abstract
1. The author deviced an apparatus for measuring tooth-mobility in which a small electromicrometer is applied.
This apparatus is composed of several parts, such as a detector, the supporting device by which the detector is fixed in oral cavity, an amplifier, and an automatic pen-recorder.
2. As this apparatus is compact and light in weight, it can be fixed easily in oral cavity and be used conveniently.
3. The most characteristic efficiency of this apparatus as compared with the tooth-mobility tester applied a dialgage is that not only the quantity of the displacement by load (tooth-mobility) can be measured but also the changes of displacement with the lapse of time (the phase of tooth-movement) can be observed.
4. However the range of measurement of this tester is within ±250μ, severe moving tooth can not be tested. And also it is unsatisfactory for the measurement of molar teeth.
