Optical Coherence Tomography in Dentistry
چکیده
New methods are needed for the nondestructive measurement of tooth demineralization and remineralization, to monitor the progression of incipient caries lesions and assess lesion activity. If caries lesions are detected early enough they can be arrested by chemical intervention and dietary changes without the need for surgical intervention. Optical coherence tomography is ideally suited to monitor the changes that occur in caries lesions, since it can nondestructively image the internal structure of the lesion with an axial resolution exceeding 10-μm. Lesions can become arrested due to the preferential deposition of mineral in the outer surface zone of the lesion. The deposition creates a highly mineralized and weakly scattering surface zone that is clearly discernable in OCT images. Since this zone is near the highly reflective tooth surface, cross-polarization OCT imaging can greatly facilitate resolution of this zone. The contrast of demineralization is also increased in the cross polarization OCT images. In this presentation, the results of in vitro OCT imaging studies employing different demineralization and remineralization regimens that produce lesions with varying mineral gradients will be discussed. Automated algorithms were developed to assess the lesion depth and severity, even with highly variable mineral gradients in the lesions. The results of recent in vivo imaging studies on natural occlusal lesions, the development of early lesions, and remineralization of lesions with fluoride will also be presented. This work is supported by research grant R01-DE17869 from the NIH/NIDCR. Biography Dr. Daniel Fried is a professor in the Division of Biomaterials and Bioengineering in the Department of Preventive and Restorative Dental Sciences at the University of California, San Francisco School of Dentistry. He received his PhD in Physical Chemistry from Wayne State University in 1992 and his thesis work involved laser ablation and spectroscopy. Dr. Fried has been a researcher in the field of laser dentistry for the past 20 years and he has published more than 180 research publications in this field. His work has included: fundamental measurements of the optical properties of dental hard tissues from the UV to the IR, studies of the interaction of carbon dioxide lasers with dental hard tissues for laser ablation of caries and the surface modification of enamel for caries prevention, the use of lasers for the selective removal of caries and composite restorative materials, the assessment of demineralization and remineralization with polarization sensitive optical coherence tomography, and the development of near-IR imaging for caries detection. He is an editor of Journal of Biomedical Optics and SPIE conference proceedings Lasers in Dentistry. Tokyo Medical and Dental University June 20-21, 2013 6 Invited Speaker Day 111:30-12:15 Expanding the Domain of Optical Coherence Tomography in Dentistry Robert Jones Assistant Professor Division of Pediatric Dentistry University of Minnesota, USA Abstract In this presentation, several important ‘expanded use’ dental OCT applications will be discussed. The main focus will be examining how cross polarization OCT can be a useful modality to further understand the process of secondary caries. Clinical investigation of composite resin restorations will be discussed with an emphasis on the need to sample and study biofilms associated with restorations in various stages of health and disease. Several examples from studies examining biofilm growth will be presented including a key validation study. The influence of composite formulations for OCT diagnostic imaging will also be presented. Lastly, this presentation will also discuss the challenges associated with using OCT for CAD/CAM fabrication.In this presentation, several important ‘expanded use’ dental OCT applications will be discussed. The main focus will be examining how cross polarization OCT can be a useful modality to further understand the process of secondary caries. Clinical investigation of composite resin restorations will be discussed with an emphasis on the need to sample and study biofilms associated with restorations in various stages of health and disease. Several examples from studies examining biofilm growth will be presented including a key validation study. The influence of composite formulations for OCT diagnostic imaging will also be presented. Lastly, this presentation will also discuss the challenges associated with using OCT for CAD/CAM fabrication. Biography Dr. Jones received his DDS and PhD after completing the Dental Scientist Training Program at University of California, San Francisco. This NIH sponsored T32 training program gave Dr. Jones a graduate education in medical and optical biomedical imaging. His PhD was completed under the mentorship of Dr. Daniel Fried, whose research career has focused on lasers and optical imaging in dentistry. He completed his Pediatric Dental Residency at UCSF in 2009 and has done research in examining biological factors in Early Childhood Caries. Dr. Jones joined pediatric dentistry faculty and collaborative research environment at the University of Minnesota in 2009. Dr. Jones is a 2010 recipient of the Faculty Development Award from the 3M Foundation. He is also a Co-PI on a funded NIH grant (Sept 2010) examining the interaction of oral biofilms and dental resin composites. He is a pioneer of dental OCT with numerous key publications on the basics and applications of the technology. His current research interests include early caries detection using near infrared based imaging, e.g. OCT, and assessing risk factors in early childhood caries. The 1st International Symposium on Optical Coherence Tomography in Dentistry 7 Invited Speaker Day 113:00-13:45 Development of a New Oral Diagnostic Tool using Optical Coherence Tomography Yasunori Sumi Professor and Director Department for Advanced Dental Research Center of Advanced Medicine for Dental and Oral Diseases National Center for Geriatrics and Gerontology, Japan Abstract Optical coherence tomography (OCT) is a new biomedical imaging modality which can generate high-resolution, cross-sectional images of microstructures in biological systems. One of the most attractive features of OCT is that it uses safe near-infrared light instead of hazardous ionizing radiation. Furthermore, resolution on the order of 10 micrometers can be obtained. The optical accessibility of clinically relevant structures in the oral cavity makes it a particularly attractive location for the application of OCT imaging techniques. Our National Center for Geriatrics and Gerontology has developed a new swept-source optical coherence tomography (SS-OCT) system by industry and public-sector joint research. This new SS-OCT system was applied for cross-sectional imaging of dental caries, resin based composite restorations, periodontal disease, oral cancer and finished dentures in this review. It is concluded that our new SS-OCT system is a promising new and useful alternative imaging technique which can safely provide much more definitive information on oral structures at far higher resolution than possible by conventional clinical imaging methods. Our National Center for Geriatrics and Gerontology has this new dental SS-OCT system of Japanese origin into the world’s first production.Optical coherence tomography (OCT) is a new biomedical imaging modality which can generate high-resolution, cross-sectional images of microstructures in biological systems. One of the most attractive features of OCT is that it uses safe near-infrared light instead of hazardous ionizing radiation. Furthermore, resolution on the order of 10 micrometers can be obtained. The optical accessibility of clinically relevant structures in the oral cavity makes it a particularly attractive location for the application of OCT imaging techniques. Our National Center for Geriatrics and Gerontology has developed a new swept-source optical coherence tomography (SS-OCT) system by industry and public-sector joint research. This new SS-OCT system was applied for cross-sectional imaging of dental caries, resin based composite restorations, periodontal disease, oral cancer and finished dentures in this review. It is concluded that our new SS-OCT system is a promising new and useful alternative imaging technique which can safely provide much more definitive information on oral structures at far higher resolution than possible by conventional clinical imaging methods. Our National Center for Geriatrics and Gerontology has this new dental SS-OCT system of Japanese origin into the world’s first production. Biography Dr. Sumi received his DDS from TMDU in 1981 and completed post-graduate course in oral surgery at Nagoya University in 1985. His primary research interest has focused on oral care for the elderly. He is the pioneer of development of dental OCT in Japan, and has worked with a number of co-investigators in the OCT project funded by Research Grant for Longevity Sciences from Ministry of Health, Labor and Welfare. Under his direction, dental SS-OCT system has been developed at National Center for Geriatrics and Gerontology of Japan. He holds several international patents related to dental OCT imaging. Dr. Sumi is also the editor-in-chief of Journal of the Japanese Society of Gerodontology and serves on the editorial board of Geriatrics & Gerontology International. Tokyo Medical and Dental University June 20-21, 2013 8 TMDU Speaker Day 113:45-14:15 SS-OCT for the Detection of Dental Caries and Tooth Crack Yasushi Shimada Cariology and Operative Dentistry Department of Oral Health Sciences Tokyo Medical and Dental University Abstract Caries diagnosis: The diagnosis of dental caries of posterior teeth is a challenge due to the restricted access for examination. Despite the dramatic decline of caries incidence, the disease is far from eradicated, particularly in children and young adults. The occlusal fissures of the first permanent molars are generally the first sites in the permanent dentition to develop caries. Although it is well accepted that bitewing radiography provides additional benefits in the detection of occlusal caries and non-cavitated proximal lesions, evidence for their value in epidemiological studies is still controversial. Dental radiographs seem to exhibit low sensitivity, but rather high specificity, while the true extent of caries lesions seems to be underestimated when relying solely on radiographs. From our in vivo and in vitro studies, Swept Source OCT (SS-OCT) showed higher sensitivity and Az values of ROC analysis than the conventional caries detection method, especially for the detection of cavitated enamel lesions and dentin caries. Tooth crack diagnosis: Cracked teeth have been a diagnostic challenge for more than half century because of the difficulty in locating crack lines of incomplete tooth fracture. Most clinicians may not find the presence of crack until they encounter complicated and diverse symptoms associated with chewing and cold. Longitudinal tooth fractures have been categorized into 5 major classes: craze line, fractured cusp, cracked tooth, split tooth, and vertical root fracture. Since a crack has an unpredictable prognosis including extraction, accurate diagnosis regarding the size and localization of the crack is required to determine the most appropriate treatment technique. SS-OCT was employed for the detection of naturally formed cracks and was capable of providing clear imaging of enamel cracks including information on penetration depth. Even when cracks extended beyond DEJ, OCT was capable of imaging the whole line, determining crack penetration depth. Biography Dr. Shimada is a senior faculty member of Cariology and Operative Dentistry. He studied dentistry and took his Ph.D. at the same institution. His extended research activities have involved characterization of dental adhesives, introducing new methodologies such as the wire-loop micro-shear bond strength test. Dr. Shimada has the experience of working at the National Institute of Standards and Technology (NIST), and has also been involved in research on pulp biological response. He is currently involved in the OCT research project with a focus on the clinical aspect, and development of an intra-oral imaging probe for chair-side imaging.Caries diagnosis: The diagnosis of dental caries of posterior teeth is a challenge due to the restricted access for examination. Despite the dramatic decline of caries incidence, the disease is far from eradicated, particularly in children and young adults. The occlusal fissures of the first permanent molars are generally the first sites in the permanent dentition to develop caries. Although it is well accepted that bitewing radiography provides additional benefits in the detection of occlusal caries and non-cavitated proximal lesions, evidence for their value in epidemiological studies is still controversial. Dental radiographs seem to exhibit low sensitivity, but rather high specificity, while the true extent of caries lesions seems to be underestimated when relying solely on radiographs. From our in vivo and in vitro studies, Swept Source OCT (SS-OCT) showed higher sensitivity and Az values of ROC analysis than the conventional caries detection method, especially for the detection of cavitated enamel lesions and dentin caries. Tooth crack diagnosis: Cracked teeth have been a diagnostic challenge for more than half century because of the difficulty in locating crack lines of incomplete tooth fracture. Most clinicians may not find the presence of crack until they encounter complicated and diverse symptoms associated with chewing and cold. Longitudinal tooth fractures have been categorized into 5 major classes: craze line, fractured cusp, cracked tooth, split tooth, and vertical root fracture. Since a crack has an unpredictable prognosis including extraction, accurate diagnosis regarding the size and localization of the crack is required to determine the most appropriate treatment technique. SS-OCT was employed for the detection of naturally formed cracks and was capable of providing clear imaging of enamel cracks including information on penetration depth. Even when cracks extended beyond DEJ, OCT was capable of imaging the whole line, determining crack penetration depth. Biography Dr. Shimada is a senior faculty member of Cariology and Operative Dentistry. He studied dentistry and took his Ph.D. at the same institution. His extended research activities have involved characterization of dental adhesives, introducing new methodologies such as the wire-loop micro-shear bond strength test. Dr. Shimada has the experience of working at the National Institute of Standards and Technology (NIST), and has also been involved in research on pulp biological response. He is currently involved in the OCT research project with a focus on the clinical aspect, and development of an intra-oral imaging probe for chair-side imaging. The 1st International Symposium on Optical Coherence Tomography in Dentistry