Multimodal imaging system for dental caries detection (original) (raw)
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Biomedical Optics Express, 2018
Early detection of dental caries is known to be the key to the effectiveness of therapeutic and preventive approaches in dentistry. However, existing clinical detection techniques, such as radiographs, are not sufficiently sensitive to detect and monitor the progression of caries at early stages. As such, in recent years, several optics-based imaging modalities have been proposed for the early detection of caries. The majority of these techniques rely on the enhancement of light scattering in early carious lesions, while a few of them are based on the enhancement of light absorption at early caries sites. In this paper, we report on a systemic comparative study on the detection performances of optical coherence tomography (OCT) and thermophotonic lock-in imaging (TPLI) as representative early caries detection modalities based on light scattering and absorption, respectively. Through controlled demineralization studies on extracted human teeth and µCT validation experiments, several detection performance parameters of the two modalities such as detection threshold, sensitivity and specificity have been qualitatively analyzed and discussed. Our experiment results suggests that both modalities have sufficient sensitivity for the detection of well-developed early caries on occlusal and smooth surfaces; however, TPLI provides better sensitivity and detection threshold for detecting very early stages of caries formation, which is deemed to be critical for the effectiveness of therapeutic and preventive approaches in dentistry. Moreover, due to the more specific nature of the light absorption contrast mechanism over light scattering, TPLI exhibits better detection specificity, which results in less false positive readings and thus allows for the proper differentiation of early caries regions from the surrounding intact areas. The major shortcoming of TPLI is its inherent depth-integrated nature, prohibiting the production of depth-resolved/B-mode like images. The outcomes of this research justify the need for a light-absorption based imaging modality with the ability to produce tomographic and depth-resolved images, combining the key advantages of OCT and TPLI.
In Pursuit Of An Optimum Optical Imaging Technology For Early Detection Of Dental Caries
Progress in Canadian Mechanical Engineering, 2018
In the last two decades, majority of the newly developed dental caries detection techniques have been opticsbased, relying either on enhancement of light scattering in early carious lesion (e.g. optical coherent tomography or OCT) or enhancement of light absorption in early caries (e.g. thermophotonic lock-in imaging or TPLI). This paper aims to explore the detection threshold capabilities between light scattering and light absorption based dental caries detection methods. With this intention, the experiments will be conducted through examination of controlled artificiallyinduced early caries. It is anticipated that the molecularcontrast TPLI imaging technology outperforms OCT due to the more specific nature of light absorption contrast
Optical Method for the Detection of Dental Caries in Oral Cavity
Optical imaging in medical field is crucial for early detection of oral diseases, to carry out more effective minimallyinvasive targeted-therapies and to restore diseased tissues functionally and aesthetically. Optical methods can be based on the properties of light scattering, absorption and fluorescence. In doing so, LEDs and classical light sources can be used. All of these methods have one basic principle in common; the optical spectrum of a tissue contains information about the biochemical composition and/or the structure of the tissue, which provide diagnostic information for tissue characterization. Among them, the most promising techniques to detect and classify different stages of caries are those based on the quantitative measurements of tooth auto fluorescence and diffuse reflectance. These techniques are non-destructive and allow detection of structural and elemental changes on the surface and inside of tissue. When tooth is irradiated with UV or blue light, several fluorophores in tissue produce a broad fluorescence distribution in the visible wavelength region. This fluorescence is referred to as the auto fluorescence, or endogenous fluorescence. Optical proprieties of caries affected tooth are different from sound tissue. Spectral imaging based on this concept may be advancement for the diagnosis of diseases
Journal of Biomedical Optics, 2003
Fluorescence loss in enamel following demineralization has been correlated with the amount of mineral lost during the demineralization. The correlation between fluorescence loss measured by quantitative light-induced fluorescence (QLF) and the reflectivity loss measured by a versatile en face optical coherence tomography (OCT) system was investigated in a demineralization process to produce artificial dental caries. We used an OCT system that can collect A-scans (reflectivity versus depth), B-scans (longitudinal images), and C-scans (en face images). The power to the sample was 250 W, the wavelength ϭ850 nm, and the depth resolution in air 16 m. A-scans, which show the profile of the reflectivity versus the depth of penetration into the tooth tissue, were used for quantitative analysis of the reflectivity loss. The results have shown that both the fluorescence radiance and reflectivity of the enamel decrease with increasing demineralization time. A linear correlation was observed between the percentage of fluorescence loss measured by QLF and the percentage of reflectivity loss measured by OCT. It was concluded that the decrease in reflectivity of the enamel during demineralization, measured by OCT, could be related to the amount of mineral lost during the demineralization process © 2003 Society of Photo-Optical Instrumentation Engineers.
Imaging carious human dental tissue with optical coherence tomography
Journal of Applied Physics, 2006
Optical coherence tomography is an imaging technology that produces high-resolution cross-sectional images of turbid media and internal microstructures including inside living tissue. In this work, three-dimensional images of a dental microstructure, that can be used to make both qualitative and quantitative assessments of oral tissue health, were obtained. It was possible to detect subclinical caries in third molar human teeth, showing that the lesion is located below the surface at 10 m with a maximum depth lesion of 50 m. A three-dimensional image was constructed confirming that it is possible to observe different planes inside the sample. It is important to notice that the optical changes induced by the carious disease in dental tissue can be readily detected by the optical coherence tomography method, before structural changes become apparent.
Journal of Biomedical Optics, 2002
New diagnostic tools are needed for the characterization of dental caries in the early stages of development. If carious lesions are detected early enough, they can be arrested without the need for surgical intervention. The objective of this study was to demonstrate that polarization sensitive optical coherence tomography (PS-OCT) can be used for the imaging of early caries lesions and for the monitoring of lesion progression over time. High-resolution polarization resolved images were acquired of natural caries lesions and simulated caries lesions of varying severity created over time periods of 1 to 14 days. Linearly polarized light was incident on the tooth samples and the reflected intensity in both orthogonal polarizations was measured. PS-OCT was invaluable for removing the confounding influence of surface reflections and native birefringence necessary for the enhanced resolution of the surface structure of caries lesions. This study demonstrated that PS-OCT is well suited for the imaging of interproximal and occlusal caries, early root caries, and for imaging decay under composite fillings. Longitudinal measurements of the reflected light intensity in the orthogonal polarization state from the area of simulated caries lesions linearly correlated with the square root of time of demineralization indicating that PS-OCT is well suited for monitoring changes in enamel mineralization over time.
American journal of dentistry, 2014
A technology based on fluorescence imaging with reflectance enhancement (FIRE) was validated for early detection of caries. In Phase-I, caries-like lesions were created in a defined window on 85 teeth by 14-day demineralization in acidified gel. During demineralization, teeth were examined for caries every 6 hours for 24 hours, and thereafter daily by visual examination (VE), FIRE, Quantitative light-induced Fluorescence (QLF), and DIAGNOdent pen (DDp). Five teeth were withdrawn after each examination. A tooth slice was cut from each window and examined under polarizing-light microscopy (PLM) for lesion presence/absence and lesion depth quantification. In Phase-II, 56 teeth assembled on mouth models were examined twice by two dentists for caries using the four methods. Each scored area was examined with PLM. Using Dentist-1/Examination-1 data, the Areas under Receiver Operating Characteristics curves (A-ROC-c) defined by each diagnostic method were compared using Chi-squared tests. ...
Clinical Monitoring of Early Caries Lesions using Cross Polarization Optical Coherence Tomography
Proceedings - Society of Photo-Optical Instrumentation Engineers, 2013
New methods are needed for the nondestructive measurement of tooth demineralization and remineralization and to monitor the progression of incipient caries lesions (tooth decay) for effective nonsurgical intervention and to evaluate the performance of anti-caries treatments such as chemical treatments or laser irradiation. Studies have shown that optical coherence tomography (OCT) has great potential to fulfill this role, since it can be used to measure the depth and severity of early lesions with an axial resolution exceeding 10-μm. It is easy to apply in vivo and it can be used to image the convoluted topography of tooth occlusal surfaces. In this paper we present early results from two clinical studies underway to measure the effect of fluoride intervention on early lesions. CP-OCT was used to monitor early lesions on enamel and root surfaces before and after intervention with fluoride varnish. The lesion depth and internal structure were resolved for all the lesions examined and...
Early Caries Imaging and Monitoring with Near-Infrared Light
Dental Clinics of North America, 2005
Enamel is highly transparent in the near infrared (NIR); therefore, this region of the electromagnetic spectrum is ideally suited for the development of new optical diagnostic tools for the detection and imaging of early dental caries. This article discusses the NIR optical properties of sound and demineralized dental enamel and the potential use of polarization sensitive optical coherence tomography (PS-OCT) and NIR transillumination for the imaging of dental caries. New diagnostic tools are needed for the detection and characterization of caries lesions in the early stages of development [1]. Conventional methods, that is, visual/tactile and radiographic, have numerous shortcomings and are inadequate for the detection of the early stages of the caries process [2-4]. Radiographic methods do not have sufficient sensitivity for early lesions, particularly occlusal lesions. By the time the occlusal lesions are radiolucent, they have often progressed well into the dentin at which point surgical intervention is necessary [4-6]. At that stage in the decay process, it is too late for preventive and conservative intervention, and a large portion of carious and healthy tissue will need to be removed, often compromising the mechanical integrity of the tooth. If left untreated, the decay will eventually infect the pulp, leading to loss of tooth vitality and possible extraction. The caries process is potentially preventable and curable. If carious lesions are detected in the enamel early enough, it is likely that they can be arrested or reversed by nonsurgical means through fluoride therapy,