Toothbrush with fluorescence means for locating dental plaque

An apparatus for detecting biological deposits on the surface of a tooth which comprises:

• illumination means to direct exciting radiation at a wavelength up to 530 nm onto a test tooth surface believed to have a biological deposit thereon,
• detection means to detect fluorescence radiation, at a wavelength associated with that of auto fluorescence emission from a substantially biological deposit-free tooth surface, emitted from the test tooth surface in response to the exciting radiation,
• conversion means to convert the fluorescence radiation into an electrical signal,
• electronic data processing means to process the electrical signal and to associate the electrical signal with the presence of biological deposits on the test tooth surface, and to make a comparison of the intensity of the said fluorescence emission from the test tooth surface with an intensity of auto fluorescence emission, at a wavelength associated with that of auto fluorescence emission from a substantially biological deposit-free tooth surface, from a tooth surface believed to have less biological deposit thereon than is believed to be present at the test tooth surface, and to associate a reduction in intensity of the auto fluorescence relative to the intensity of auto fluorescence from a tooth surface known to have less biological deposit thereon than is present on the test tooth surface with the presence of biological deposits on the test tooth surface, and,
• indicator means to indicate the presence of such biological deposits to a user of the device.