Optical Measurement of Blood Oxygen Saturation of Dental Pulp

The applicability of arterial pulse oximetry to dental pulp was demonstrated using in vitro and in vivo measurements. First, porcine blood of known oxygen saturation (SO 2 ) was circulated through extracted human upper incisors, while transmitted-light plethysmography was performed using three different visible wavelengths. From the light intensity waveforms measured in vitro , a parameter that is statistically correlated to SO 2 was calculated using the pulsatile/nonpulsatile component ratios of two wavelengths for different SO 2 . Then, values were measured in vivo for living incisors, and the corresponding SO 2 values were calculated using the results of in vitro measurements. The estimated SO 2 values of the upper central incisors measured in vivo were from 71.0 to 92.7%. This study showed the potential to measure the oxygen saturation changes to identify the sign of pulpal inflammation.