牙齿龋齿损伤可见-近红外光谱偏振检测研究

针对不同龋齿损伤程度有效表征问题，探究一种光谱偏振无损低耗的检测方法，作为对常规检测方法如化学分析法、表面轮廓测定法、显微放射照相术的有益补充。牙齿龋齿损伤由脱矿溶解牙釉质与牙本质的钙与磷酸盐造成，牙齿组织表面微观结构发生了不同程度的变化，结构的变化导致其对光波散射特性与相位改变呈现不同程度的差异。基于偏振光谱对观测样本表面微观结构敏感的特征，不同龋齿损伤样本其表面微观结构变化与偏振信息强烈关联，提出一种光谱偏振有效表征牙齿龋齿损伤度的方法。分别选取450，550，670和860 nm四个不同观测光谱研究波段，选择六个不同龋坏程度的实验样本，选取偏振度参量描述不同牙齿样本的光谱偏振特性。实验结果表明，同一观测光谱波段随着牙齿龋坏程度的加深其偏振度表征参量呈现增加趋势，同时，对于同一观测样本450 nm光谱波段的偏振特性强于其他波段，呈现观测光谱波段与其偏振特性负相关关系。为进一步定量刻画偏振光谱与牙齿龋坏损伤等级的表征关系，构建光谱偏振特征参量与不同损伤等级牙齿样本的指数关联数学模型，通过数学模型解译其内在耦合关联。为有效验证构建模型的稳健性，对模型仿真预测结果与实测数据进行定量化验证，选取和方差（SSE）、模型确定系数（R-square）、均方根（RMSE）等评价因子对构建的模型进行定量评判。结果表明，四个不同光谱波段的模型确定系数均接近于1，和方差与均方根数值均较小，且450nm观测光谱波段接近于0，定量评价结果验证了构建模型的稳健性与有效性，构建模型可有效解译不同龋齿样本与光谱偏振特征的耦合关联。该研究内容有效扩展了牙齿龋齿检测方式，揭示了光谱偏振可有效表征龋齿损伤，发展了一种无损低耗的新型偏振光谱检测技术手段。

Research of Dental Caries Lesion Based on the Visible-Near Infrared Spectrum Polarization Detection

In view of the problem to effectively characterize the damage of dental caries,we explore a kind of polarization spectrum detection method which have nondestructive and low consumption characteristics,it’s a beneficial to supplement for the conventional detected methods such as chemical analysis,surface profilometry and microradiography.Based on the characteristic which polarization spectral sensitive to the observation sample surface microstructure,dental caries lesion due to the demineralization process,as result calcium and phosphate are dissolved from the enamel and dentin.The tooth surface microstructure has taken place different change;the structure present different degree of difference in light scattering properties and phase change.Considering different dental caries samples its surface microstructure changes strongly associated with the polarization information,we put forward a kind of method which can effectively characterize different teeth from caries by using polarization spectrum.Selected the 450,550,670 and 860 nm as four different observation research wavelengths,as well as selected six different dental caries samples,the degree of polarization as the parameter to describe different samples polarization characteristics.The experimental results show that the consistent observation waveband for different tooth samples is positively related to the degree of polarization parameters,as well as the same observation samples showed observation waveband is negatively related to the polarization characteristics.For further quantitative characterization,the relationship between polarization spectrum and tooth decay damage levels,the index correlation mathematical model which can interpret internal coupling was built.To effectively validate model robustness,it needed quantitative validation the model simulation results and measured data.We selected the quantitative evaluation factor such as the sum of squares due to error(SSE),root means squared error(RMSE),coefficient of determination(R-square).The results show that models R-square close to 1,as well as the SSE and RMSE values are small.The model characteristic of robustness and effectiveness was verified,which can effectively interpret different caries damage teeth samples from polarization coupling relation.This research is effectively extending the teeth caries detection method,as well as revealed polarization spectrum can be effective characterization and distinction to different dental caries samples.It is also developing a new kind of nondestructive and low-cost polarization spectrum detection technology.