Theory And Experimental Study Of Dental Caries Detection Based On The Effect Of Fluorescence

Dental caries has always been an important disease which is harmful to human health.With the improvement of living standards and the change of people's diet habits and structure , the scope of dental caries has become more and more wide and the threat of the disease has become more and more serious since the 20th century. Now , dental caries has been classified as one of the three diseases which should be prevented and treated as a global focus by the World Health Organization. Thus, an effective caries prevention, early detection and treatment is becoming increasingly concerned about as a human issue.Clinically, detection methods for early detection of dental caries has been studied by a multi-disciplinary combination of mechanical, electrical and other subjects. At present a lot of significant progress has been made in this area. However, higher demands to early detection are asked for because the serious status of oral health . Optical methods for early caries detection are being paid more and more attention by many researchers because of their advantages. Around the application of optical methods in the detection of dental caries, theoretical and experimental methods based on fluorescence effects are discussed in detail in this paper.Optical caries detection technologies which are applied widely are discussed systematically in the first chapter. Each technology route is introduced in detail and various biological mechanism is described deeply. At the same time, a brief introduction on tooth structure and some basic theory of the dental caries change are given.As a research topic in biological tissue optical area , the bio-tissue optical transmission theory and scattering, absorption property are introduced in the second chapter, besides, optical parameters which describe the characteristics above are defined. The fluorescence effects of biological tissue and the basic concept of fluorescence spectra are focused. Meanwhile, the fluorescence characteristics of teeth is introduced.The origin, principle and relevant steps of the Monte Carlo algorithm are discussed in detail in the third chapter, besides the simulation model is given. By setting the absorption coefficient, scattering coefficient, refractive index and fluorescence quantum efficiency of the model, the fluorescence intensity simulation study of dental models based on the algorithm called Monte Carlo is completed . Different fluorescence distribution photos between healthy organizations and different decay profiles ones are obtained respectively.At last, the rationality is verified with the fluorescence simulation function of Tracepro.In chapter four, experimental systems are designed, two-dimensional and three-dimensional fluorescence spectra of different pathological tooth samples are measured with lasers and xenon lamp respectively. Experimental results show that physical changes in the composition of the organization happens with the deepening of pathological changes in the teeth, the absorption peak of two-dimensional fluorescence spectra of in the 560nm changes, which could be characterized to determine whether dental caries changes occurred. The fluorescence energy of three-dimensional spectrum in the 430-460nm band increases, in other words ,the relative distribution proportion becomes larger, while the relative distribution of energy in the 390-435nm is reducedTherefore , detection of dental caries which is based on fluorescence spectral characteristics is demonstrated and supported.A comprehensive summary of the current study and future work prospects are mainlyrelated in chapter five.