Research On The Detection Method Of Cracked Tooth Based On OCT Technology

Tooth cracks,periodontal disease and dental caries are three major causes of tooth-loss in adult.But the symptoms of tooth cracks are hidden,and the existing imaging technology has insufficient resolution,which is difficult to detect accurately.Optical Coherence Tomography(OCT)technology has the advantages of non invasion,no radiation to human body,high resolution,and small equipment.There are few researches on the application of OCT technology in the detection of tooth cracks.Although OCT has been proven that it is effective for tooth cracks imaging,there is a lack of research on the location of tooth cracks lesions,detection of disease progression,and grade detection.The model also has the problems of uncontrollable preparation.For the above problems,the main research work in this paper is as follows:First,System design and construction.According to the needs of crack detection,a suitable OCT system is designed and built,which realize the complete crown coverage scanning.The optical path of the system is composed of Mach-Zehnder interferometer.The horizontal scanning of system built in this paper uses the optical path deflection,the scanning device is designed based on the scanning galvanometers,and a program is written to complete the synchronous control of OCT.The system has an axial resolution of 8.61?m and the lateral resolution of 18.7?m.Second,OCT image 3D reconstruction and registration.Because the optical path deflection method is used for the horizontal scanning of the system,the scanning path is a sector,and the collected data needs to be corrected to obtain the tooth tomographic sequence.The Gauss filter is used to denoise the tomographic sequence,three-dimensional reconstruction of the tooth tomographic sequence is implemented using the ray-casting algorithm,and use three-dimensional model to realize the location of tooth crack.At the same time,in order to monitor the direction of the crack in the internal tissue of the tooth,iterative Closest Point(ICP)algorithm is used to solve the problem of registration of tomographic images data from different perspectives.Thirdly,Experiment and result analysis.Based on the comparison of the method of obtaining the cracked model in the research,combined with the causes of crackedin the oral environment,temperature difference method is proposed to prepare the tooth cracked model.The imaging results of the system show that the swept source OCT system built in this paper can detect different grades of tooth cracks,and through the three-dimensional model and two-dimensional registration image,the progress of tooth cracks development can be monitored.By comparing the cracks before and after the preparation,and the SPSS software is used for statistical analysis.It is verified that the temperature difference method can effectively prepare the tooth cracked model in vitro,and different grades of tooth cracks can be obtained by changing the preparation time and the number of preparation cycles.The Swept source OCT system constructed in this paper can realize the tooth cracks monitoring and classfication detection,and it is of great significance for the clinical diagnosis and treatment of tooth cracks.