Abstract: An optical technique and device for assessing tooth vitality, involving the use of trans-illumination to detect differentially the relative absence of light absorbed by hemoglobin in circulating blood inside a healthy tooth. White light received from an illuminated healthy tooth is relatively devoid of intensity at a wavelength characteristic of absorption by hemoglobin, when compared with light following the same path in the tooth but of a longer wavelength, by taking the ratio of intensities of the two wavelengths the light of one wavelength is relatively more absorbed by hemoglobin or oxyhemoglobin than the other, indicating the relative amount of blood or oxygen in the blood present in the tooth at the time of the measurement. A broad-spectrum light source is rigidly coupled to a split-beam, differentially-filtered photometer incorporating relatively narrow band filters. Vitality is assessed from the ratio of the scattered light at the two wavelengths, and in change of this ratio overtime.

Abstract: A sensing device for obtaining optical density or light scattering measurements or other, in a turbulent liquid comprising a light source and a facing sensor located within a housing. The housing is provided with orifices through which liquid flows into the housing for measurement. The liquid entering the housing is slowed by passage through the orifice, and the bubbles of the liquid rise to the upper region of the housing, out of the measurement region, e.g. out of the line of the sight between the light source and the sensor.