【作者】 朱海华；

【导师】 陈晖；

【作者基本信息】 浙江大学 ， 口腔内科学（专业学位）， 2015， 博士

【摘要】 目的：龋病是世界范围内广泛存在的口腔常见疾病,我国患龋率高达90%以上。随着口腔保健意识的增强,龋齿风险评估和早期检测成为口腔临床医学领域面临的重要问题。本论文从自体荧光光谱技术角度展开研究,为无创、准确、可定量的光学诊断技术应用于龋病精确化防控奠定实验基础。方法及结果：①应用荧光分光光度计对6种龋病相关微生物逐一进行光谱表征参数分析,发现6种龋病相关微生物在随着激发波长的递增,发射波出现了红移的现象；6种龋病相关微生物在350nm激发波长下,均存在436+4nm的特征荧光峰位值,提示此特征荧光来自于非卟啉物质。加血培养促进了龋病相关微生物的自体荧光代谢环境,微生物浓度与荧光强度之间存在线性正相关。②通过模拟口腔环境,形成不同致龋强度的人工菌斑,测试获得菌斑荧光光谱表征参数。结果显示培养第8天,1%蔗糖浓度组的菌斑溶液荧光强度高于其他蔗糖浓度组(P<0.05)。部分实验组荧光强度第8天高于第4天(P<0.05)；采用逐步回归分析方法设立了牙釉质片微硬度下降百分比、细菌粘附度与荧光参数的函数关系。③采用荧光分光光度计获得不同龋损程度离体牙在405nm波长激发下的荧光光谱分布特征,结果显示荧光光谱面积比率值P与龋齿检测仪DD值之间具有较好的线性关系(R=-0.9085)。分析了不同激光功率和不同检测部位对荧光光谱表征参数的影响。④在健康及不同龋损程度离体牙的荧光光谱特征参数基础上,分析了龋损等级与荧光面积比率值的关系(P<0.01),龋损等级与主波长的关系(P<0.01),荧光面积比率值α与荧光图像分量比率p的关系(P<0.01),根据ROC分析方法获得了荧光图像分量比率β的龋损分级标准。结论：本文探索了龋病相关微生物、人工菌斑、健康及不同龋损程度牙体组织的自体荧光光谱特征；通过荧光强度对口腔微生物进行定量化分析是可行的；研究了人工牙菌斑的荧光光谱表征性参数与其致龋性的关系；设立了基于龋损组织自体荧光光谱参数的荧光光谱面积比率值、荧光图像分量比率值,为基于自体荧光技术的龋活跃性评价和龋损分级提供了理论依据,为后期的龋齿检测仪研发提供必要的实验基础。更多还原

【Abstract】 Objective:Dental caries is a widespread disease and its morbidity rate in China is as high as90%. With the enhancement of public awareness, the early detection of dental caries presents an important problem in the field of dental public health. Based on the autofluorescence spectrum technique, this thesis aims to study the optical detection of caries with the characteristics of nondestructness, validity and quantitativeness and lay the experimental foundation for the precise control of dental caries.Methods and results:①The spectra parameters of6kinds of caries-related microorganisms were analyzed by fluorescence spectrophotometer. It was shown that the emission wavelength turned to the red side with the increase in excitation wavelength.For all six microorganisms, the fluorescence peak located at436±4nm with350nm excitation wavelength, which means that the fluorescence was not derived from porphyry compounds and had great significance for gram positive bacteria.The blood culture promoted the autofluorescence of microorganisms. There was a significant linear correlation between fluorescence intensity and microorganisms concentration. The proposed parameter of fluorescence intensity ratio FIRA could be used to identify streptococcus mutants.②Dental biofilms with various levels of carcinogenicity were grown and their fluorescence spectrum was detected individually. In the8th day, the fluorescence intensity of biofilms with1%sucrose concentration groupwas higher thanthe other groups (P<0.05);Part of the experimental group fluorescence intensity in the8th day was higher than the4th day (P<0.05). The functional relationship between fluorescence parameters and carcinogenicity indexes (%SHC and Adhesivity) was analyzed by stepwise regression analysis②The fluorescence spectrum characteristics of various caries level were determined in vitro at405nm exciting light by fluorescence spectrophotometer. The results showed that there was a good linear relationship between the fluorescence spectrum area ratio value P and the DD value of DIAGNOdent pen (R=-0.9085). The different laser power and position of teeth could affect the fluorescence spectrumcharacteristic parameter.④Based on the fluorescence spectrum parameters ofhealth and various carious teethin vitro, there were analyzed the relationship between the different carious level with fluorescence spectrum area ratio a (P<0.01), the relationship between the different carious level with dominant wavelength (P<0.01), the relationship between fluorescence spectrum area ratio α and fluorescence imaging component ratio β (P<0.01).According to the ROC analysis method, the quantitative classification for carious teeth using fluorescence spectrum area ratio α was developed.Conclusions:This paper explored the autofluorescence spectra characteristics of carie-related microorganisms, artificial biofilm and tooth tissue. It was feasible to quantitative analysis of carie-related microorganisms by the fluorescence intensity. The correlation between fluorescence spectroscopy parameters and cariogenicity of biofilm would provid the experimental evidence for caries risk assessment. The quantitative evaluation of dental caries based on the autofluorescence spectra parameters was set up. Meanwhile, this article developed the evaluation criteria of fluorescence imaging and chroma of dental caries. It would be meaningful to develop the early carious detector based on fluorescence technique.更多还原