To determine presence or absence of adhesion of dental plaque in teeth with high accuracy.SOLUTION: A determination device is configured so as to determine whether or not a sensor head is clean, based on: strength of fluorescence of a first wavelength band showing a peak of fluorescence of dental plaque included in the fluorescence received by a sensor head strength of the fluorescence of a second wavelength band reduced in the peak of the fluorescence of the dental plaque showing the peak in the first wavelength band the presence or absence of the detection of teeth 210 by detecting the strength of the fluorescence from the teeth 210 and the strength of the fluorescence of the first wavelength band and the strength of the fluorescence of the second wavelength band.SELECTED DRAWING: Figure 2【課題】歯牙における歯垢の付着の有無を高精度に判定すること。【解決手段】センサヘッドによって受光された蛍光に含まれる歯垢の蛍光発光のピークを示す第1の波長帯域の蛍光の強度と、第1の波長帯域においてピークを示す歯垢の蛍光発光のピークが小さくなる第2の波長帯域の蛍光の強度と、歯牙210からの蛍光の強度を検出し、歯牙210の検出の有無と、第1の波長帯域の蛍光の強度と第2の波長帯域の蛍光の強度とに基づいて、センサヘッドが清浄であるか否かを判定する判定装置を構成した。【選択図】図2
