通过研究激光与牙齿组织相互作用机理及组织再发射光谱与组织光学特性之间的关系,提出了一种将后向散射光,反射光以及自体感生荧光三者相结合的新型荧光光谱龋齿诊断方法。激光与龋齿相互作用过程中,不仅产生反射光,还会产生自体荧光和后向散射光,而这些后向散射光和自体荧光含有有关龋齿组分、结构、空间构象等的大量信息。为了获得三种信息和龋损状态的关系,实验建立了离体龋齿的组织光谱诊断装置,该装置以频率与细菌特征频率相近的He-Ne激光为激励源,激光器的功率为(2.0±0.1) mW,在不采用滤光片的情况下获得了104个离体样本的荧光光谱,以瑞利散射为特征光谱的标准化参数,定义了表征组织形态变化的反斯托克斯散射归一化系数C1和表征牙组织病理变化的斯托克斯荧光归一化系数C2,结合两者对离体龋齿的龋损状态进行表征。实验结果表明,该方法克服了现有的激光龋齿诊断方法的不足,能够准确表征离体龋齿的龋损状态,并且对早期的白点龋,填充的牙齿和牙结石的诊断更敏感。

A new caries detection method of fluorescence spectrum which contains backscattering, back-reflected and auto-fluorescence is proposed after researching on the interaction mechanism of laser with dental tissue and relationship between remitted light and optical properties of the tissue. Not only auto-fluorescence but also back-reflected and back-scattering were produced in the process of the interaction. All of these lights contained rich information related with caries components, structure, spatial conformation, and so on. In order to obtain the relationship between those information and various stages of dental caries, an experiment of caries in vitro was designed and carried out. Investigation was performed on 104 samples by using He-Ne laser (λ=632.8 nm,2.0±0.1 mW) as a source of probing radiation. Using the Rayleigh scattering to normalize the intensity of measured spectrum, we defined anti-Stoke′s scattering normalization coefficient C1, which can describe morphological changes in dental tissue, and Stoke′s fluorescence normalization coefficient C2, which can describe chemical changes in tooth, and then, we evaluate various stages of dental caries by analyzing two normalization coefficient of caries characteristic spectrum. Preliminary results showed a high potential of using this new method to diagnose various stages of dental caries, and it is more sensitive to white caries, filling and Dental calculus.