Optical diagnosis method for dental pulp viability based on the blood oxygen saturation using short wavelength LED

牙髓活力评估是牙科治疗的重要诊断程序。由于血管供应是评估牙髓活力最准确的决定因素，我们开发了采用525nm LED的透射光体积脉搏仪（TLP）系统来检测牙髓组织的微循环变化。本研究以牙髓血氧水平（SO_2）作为牙髓活性与牙髓炎症关系的附加信息，并试图通过体外实验建立基础理论。将带氧和无氧的人体血液循环于取出的人类上门牙中，模拟牙齿体积图。在SO_2的计算中，采用峰值发射波长为470nm、525nm和590nm的3个led，测量了脉冲波的振幅（V_<p-p>）和透射光强（V_t）。结果表明，在470和590nm， 525和590nm处计算的φ(ln(V_<p-p>/V_t))的比值与实际SO_2呈线性关系。

Assessment for the dental pulp vitality is a crucial diagnostic procedure for the dental treatment. As the vascular supply is the most accurate determinant for assessing pulp vitality, we have developed the Transmitted-light Plethysmography(TLP) system with 525nm LED to detect microcirculatory changes in the pulp tissues. In this study, we focused on the pulpal blood oxygen levels(SO_2) as additional information for pulp viability in relation to pulpal inflammation, and attempted to establish the basic theory by in vitro study. The oxygenated and deoxygenated human blood was circulated through the extracted human upper incisors to simulate the tooth plethysmogram. For computation of SO_2, the amplitudes of pulse waves(V_<p-p>) and transmitted light intensity(V_t) were measured using three LEDs with peak emission wavelength at 470nm, 525nm and 590nm. Results indicated ratio ofφ(ln(V_<p-p>/V_t)) computed by 470 and 590nm, 525 and 590nm showed linear relationship with actual SO_2.