| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure a periodontal pocket without pain to a patient by providing a lens, a projection fiber, a photo detecting fiber and a detector for detecting an overlap of a projection area and a photo detecting area, and visually confirming a scale according to a detection signal from the detector. SOLUTION: Projected light from a projection lens 13 is reduced in light flux by a lens 5, and an inclination is given to a projection axis by a deflecting lens 16 to make a comparatively small crossed axes angle in a space up to the photo detecting axis of reflected light. When the projection light flux is reflected in a predetermined position P2, it is mostly reflected to enter the deflecting lens 16 as a photo detecting light flux to be corrected in its direction and sent to a signal processor through a photo detecting fiber 19, and the fact is informed from a speaker. The photo detecting amount at the position of P2 is larger as compared with those in the positions of P1 and P3, so that, when the vertical position of a scale cover 25 is adjusted, the position of P2 can be detected. That is, the position of P2 is the base of a periodontal pocket, and when a scale 14 to a fixed point at this time is read, the depth of the periodonal pocket is found.
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