| Dental resin,with its good physical and chemical properties and easy handling,has successfully replaced traditional silver amalgam and has become the preferred material for tooth restoration.However,the average lifespan of resin restorations lags behind that of amalgam.The main reasons are fracture of restorations caused by insufficient mechanical properties of the materials,edge cracks and secondary caries caused by polymerization shrinkage or thermal expansion coefficient mismatch.Therefore,in order to understand the dynamic curing properties of dental resin,a number of curing monitoring methods have been developed,such as: B.differential scanning calorimetry,dynamic thermomechanical analysis,dielectric analysis and so on.However,most of these methods are contact methods and cannot effectively characterize the full curing process of resin restorations.In this thesis,a new method based on phase-sensitive optical coherence tomography for monitoring dental restorations is proposed.The non-contact measurement of tooth solidification dynamics is realized by the non-contact measurement option of optical coherence chromatography.In addition,it also realizes a time-resolved visualization monitoring of the dental resin restoration process by utilizing the properties of interferometric phase sensitivity,which is a powerful means of monitoring the dental restoration.The main research topics of this work include:（1）Based on the basic principle of OPTICAL coherence chromatography,a spectral domain optical coherence chromatography system was developed for the monitoring of dental resin restorations with a resolution of 5.2 μm and a depth range of 3.3 mm.The system was used to monitor three types of dental resins commonly used in the clinic.The experimental results show that phase-sensitive optical coherence tomography can be used to quantitatively measure the refractive index change and contraction stress of dental resins during curing,and that non-contact characterization of the curing kinetics of dental resins can be realized.（2）A full-field hardening measurement method for dental resin based on phase-sensitive optical coherence tomography was established.The optical path difference depth gradient was used as a cure monitoring index to achieve visual monitoring of the internal curing process of dental resin with time-space resolution.To verify the effectiveness of the method,setting monitoring experiments were performed on single and double dental resin.Experimental results showed that the depth-dependent gelation process of monolayer resin or the difference in curing speed of bilayer resin was observed,confirming that the method could realize the visualized monitoring of the depth-resolution curing process of dental resin.（3）In order to further verify the method of phase-sensitive optical coherence tomography for teeth to repair the practical value,it also simulates the actual process of tooth repair in the clinic,samples were prepared in vitro teeth,dental resin dripping into the in vitro and the hole in the hardening of the tooth compartment and synchronization with the experimental system for visual monitoring of the hardening process of the tooth resin.The clear boundary between dental resin and tooth can be observed from the cross section of the test results,and the hardening mechanism of dental resin in time and space can be deduced by combining the changing trend of the hardening degree of dental resin and the distribution of hardening degree and hardening speed in corresponding time.The feasibility of using phase-sensitive coherence chromatography to visually monitor the full setting process of a dental restoration has been demonstrated. |
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