%0 Journal Article
%T Optical Measurement of Blood Oxygen Saturation of Dental Pulp
%A Satoko Kakino
%A Shinya Kushibiki
%A Azusa Yamada
%A Zenzo Miwa
%A Yuzo Takagi
%A Yuji Matsuura
%J ISRN Biomedical Engineering
%D 2013
%R 10.1155/2013/502869
%X 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 (SO2) 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 SO2 was calculated using the pulsatile/nonpulsatile component ratios of two wavelengths for different SO2. Then, values were measured in vivo for living incisors, and the corresponding SO2 values were calculated using the results of in vitro measurements. The estimated SO2 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. 1. Introduction Diagnosing a dental pulp condition is important in clinical practice, but it is hard because dental pulp is covered by calcified tissue which makes it difficult to get objective parameters of pathological conditions. Conventional vitality tests of dental pulp, which are based on sensory nerve response to thermal and electrical stimulation, have limitations in terms of accurate diagnosis [1, 2]. Since these tests require a subjective response from the patient, they can result in false positives, particularly in case of the pediatric patient. In addition, with immature permanent or traumatized teeth, false negative results can occur due to increased sensory nerve thresholds. The dental pulp microcirculation system plays an essential role in maintaining tooth homeostasis, and pulp vitality depends on the function of the vascular system rather than that of the neural response. Several noninvasive and objective methods have been proposed for assessing the circulatory status of dental pulp, including laser Doppler flowmetry [3, 4], dual wavelength spectrophotometry [5], and optical plethysmography [6, 7]. We previously developed a method called ¡°transmitted-light plethysmography (TLP)¡± that optically detects circulatory changes in the blood flow and investigated the applicability of TLP to the vitality test of traumatized teeth [8]. It works by detecting the pulsation intensity of light transmitted through a tooth. It uses light with a wavelength of 525£¿nm from an LED and visualizes the pulpal blood flow synchronized with the heartbeat. We have used TLP in clinical practice to examine pulp vitality in traumatized teeth and found that the pulse amplitudes (pulse
%U http://www.hindawi.com/journals/isrn.biomedical.engineering/2013/502869/