FIELD : medicine.SUBSTANCE : group of inventions refers to medicine, namely dentistry and can be used for diagnosing dental caries at all stages. Preliminary formed databases of confirmed caries pathologies of teeth, including at least one preliminary criterion of dental caries. Optical characteristics of recording devices are measured in different spectral ranges of recording. Spectral registration areas are determined, where for each pathology of teeth contained in the database, the recording device provides an output image in the visible spectrum with maximum optical contrast of the localized carious area of the tooth to the rest of the tooth and/or a maximum value of the output electrical signal. A diagnostic device is used for diagnostic examination of a recording device with an optical radiation receiver with maximum optical contrast sensitivity and/or a maximum value of the output signal for each pathology. Calibration measurements of recording devices are carried out in spectral range of sensitivity of their optical elements. Each of the confirmed carious pathology of tooth is matched with each image obtained at the output of the recording device with a localization center of carious regions or/and definite response from the output of the recording device in the form of an electrical signal. Calibration measurements data are entered into a database. Data of the current diagnostic examination are compared with data of the database and substantiation of the conclusion on at least one preliminary criterion of dental caries or stages of caries development.EFFECT : group of inventions provides higher accuracy of diagnosing dental caries at the stage of its origination and development during mass examination of the population and diagnosis of dental caries in all areas, including in fissures, interdental surfaces, in cervical areas, on smooth, open and closed surfaces of teeth and other areas of oral cavity.3 cl, 1 dwg