Research On Detection Of Caries By Terahertz Spectroscopy And Imaging

Caries is one of the most common oral diseases in the world.In recent years,with the improvement of people’s awareness of oral cavity protection,the research on the new nondestructive detection method of dental caries has gradually become a research hotspot in the field of oral medicine.Compared with X-ray,terahertz wave has low ionizing radiation,which is relatively safe for biology,and can reflect the characteristics of the substance itself through fingerprint spectrum.Therefore,terahertz spectroscopy is expected to be a new technology for rapid nondestructive detection of dental caries.In this paper,the human tooth grinding samples containing dentine caries are taken as objects and studied by using terahertz spectroscopy.The main research contents are as follows: 1)Introduced the research status of terahertz technology in the field of biological detection,and analyzed the extraction methods of terahertz spectrum parameters.2)Established the the transmission and reflection terahertz spectral detection systems to obtain spectral characteristic curves of enamel,dentin and dentin caries,and analyzed the differences among them and performed the statistical significance test.3)Studied the terahertz spectral scanning imaging of caries samples in the transmission and reflection modes,and constructed the terahertz images of different parameters to find the best imaging method.Compared with the results of Xray imaging,it is proved that the phase difference imaging of terahertz spectral got better caries identification effect.4)Used the image fusion method based on wavelet gradient domain reconstruction to effectively solve the defects of caries reflection terahertz image,and improve the image quality and enhance the detection effect of caries.The innovation points of this research mainly include:(1)The experimental results show that terahertz refractive index and reflectance parameters can effectively identify dentin caries,which is of great significance in the field of dentistry.In the transmission mode,phase difference imaging has the best detection effect of caries.By comparing the detection area of dental caries with that of light microscopy,it is proved that terahertz imaging can identify the disintegrating layer and invasion layer of dental caries with bacterial invasion,which is the key detection part in clinical dental caries diagnosis and treatment.(2)Using the fusion method based on gradient domain Haar wavelet reconstruction,the same samples of different frequency of terahertz effective information fusion image to an image,image dynamic range from 0～150 to 0～255,contrast and average gradient index increased to more than 2 times,sample edge is more clear,the effect of the enhanced image caries detection.This study confirms the great potential of terahertz spectroscopy in the field of tooth nondestructive testing,and provides a new processing idea for the optimization of terahertz medical images.