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Hund SMM, Golde J, Tetschke F, Basche S, Meier M, Kirsten L, Koch E, Hannig C, Walther J. Polarization-Sensitive Optical Coherence Tomography for Monitoring De- and Remineralization of Bovine Enamel In Vitro. Diagnostics (Basel) 2024; 14:367. [PMID: 38396406 PMCID: PMC10888132 DOI: 10.3390/diagnostics14040367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 01/25/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Early caries diagnosis still challenges dentistry. Polarization-sensitive optical coherence tomography (PS-OCT) is promising to detect initial lesions non-invasively in depth-resolved cross-sectional visualization. PS-OCT with determined degree of polarization (DOP) imaging provides an intuitive demineralization contrast. The aim of this study is to evaluate the suitability of DOP-based PS-OCT imaging to monitor controlled de- and remineralization progression for the first time and to introduce it as a valid, non-destructive in vitro detection method. Twelve standardized bovine enamel specimens were divided in different groups and demineralized with hydrochloric acid (HCl) as well as partly remineralized with fluoride over a 14-day pH-cycling experiment. The specimens were stored in artificial saliva and sodium chloride (NaCl), respectively. Progress measurements with PS-OCT were made with polarization-sensitive en faceand B-scan mode for qualitative evaluation. The specimens demineralized in HCl showed the most pronounced surface change (lowest DOP) and the most significant increase in depolarization. Additional fluoride treatment and the storage in artificial saliva resulted in the opposite (highest DOP). Therefore, DOP-based PS-OCT imaging appears to be a valuable technique for visualization and monitoring of enamel demineralization and remineralization processes in vitro. However, these findings need to be confirmed in human teeth ex vivo or in situ.
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Affiliation(s)
- Stella M M Hund
- Department of Medical Physics and Biomedical Engineering, Faculty Carl Gustav Carus of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
- Polyclinic of Operative Dentistry, Periodontology and Pediatric Dentistry, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Jonas Golde
- Department of Medical Physics and Biomedical Engineering, Faculty Carl Gustav Carus of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Florian Tetschke
- Polyclinic of Operative Dentistry, Periodontology and Pediatric Dentistry, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Sabine Basche
- Polyclinic of Operative Dentistry, Periodontology and Pediatric Dentistry, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Melina Meier
- Polyclinic of Operative Dentistry, Periodontology and Pediatric Dentistry, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Lars Kirsten
- Department of Medical Physics and Biomedical Engineering, Faculty Carl Gustav Carus of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Edmund Koch
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Christian Hannig
- Polyclinic of Operative Dentistry, Periodontology and Pediatric Dentistry, Faculty of Medicine Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Julia Walther
- Department of Medical Physics and Biomedical Engineering, Faculty Carl Gustav Carus of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany
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Ng M, Wycoff S, Zhu Y, Ho YC, Takasuka H, Fried D. Time-resolved SWIR imaging for the assessment of the activity of occlusal caries lesions. JOURNAL OF BIOPHOTONICS 2023; 16:e202300165. [PMID: 37316468 PMCID: PMC10846334 DOI: 10.1002/jbio.202300165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 06/16/2023]
Abstract
The aim of this study was to develop a clinical SWIR reflectance handpiece to assess the activity of lesions on the occlusal surfaces. The time-resolved reflectivity of 10 active and 10 arrested occlusal caries lesions on extracted teeth was monitored at 1470 nm using a benchtop system and a modified clinical prototype during forced air drying. The presence of a highly mineralized surface layer measured with microcomputed tomography (microCT) was used to indicate lesion activity. Multiple kinetic parameters were extracted from the acquired SWIR time versus intensity dehydration curves and used to assess lesion activity. Three parameters: delay, %Ifin , and rate calculated from the SWIR dehydration curves were significantly different (p < 0.05) between active and arrested lesions. The modified clinical probe was able to completely dehydrate all the active lesion areas in the occlusal pits and fissures in less than 30 s.
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Affiliation(s)
- Morgan Ng
- University of California, San Francisco, San Francisco, California 94143-0758
| | - Spencer Wycoff
- University of California, San Francisco, San Francisco, California 94143-0758
| | - Yihua Zhu
- University of California, San Francisco, San Francisco, California 94143-0758
| | - Yi-Ching Ho
- University of California, San Francisco, San Francisco, California 94143-0758
- Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan 11217
| | - Hannah Takasuka
- University of California, San Francisco, San Francisco, California 94143-0758
| | - Daniel Fried
- University of California, San Francisco, San Francisco, California 94143-0758
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Yang Y, Xue Q, Zhang Y, He X, Li Z, Yang J. Quantitative analysis of the degree of demineralization for bleached enamel by optical coherence tomography. Photodiagnosis Photodyn Ther 2023; 43:103686. [PMID: 37399915 DOI: 10.1016/j.pdpdt.2023.103686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/14/2023] [Accepted: 06/30/2023] [Indexed: 07/05/2023]
Abstract
BACKGROUND Tooth bleaching imparts whitening effects along with adverse effects such as increased tooth sensitivity and enamel surface changes. Herein, we employed optical coherence tomography (OCT), a nondestructive optical detection technique, for evaluation of tooth enamel after treatment with peroxide-based bleaching agents. METHODS Fifteen enamel samples were bleached using 38% acidic hydrogen peroxide-based bleach, subjected to OCT scanning, and then cross-sectioned and imaged under polarized light microscopy (PLM) and transverse microradiography (TMR). OCT cross-sectional images were compared with PLM and TMR. The depth and severity of demineralization produced in the bleached enamel were measured by OCT, PLM, and TMR. Comparison between the three techniques was performed using Kruskal-Wallis H non-parametric test and Pearson correlation. RESULTS In comparison with PLM and TMR, OCT clearly detected the changes in the enamel surface after hydrogen peroxide bleaching. Significant correlations (p<0.05) were observed in lesion depth between OCT and PLM (r=0.820), OCT and TMR (r=0.822), and TMR and PLM (r=0.861). There was no statistically significant difference in demineralization depth values measured by OCT, PLM, and TMR (p>0.05). CONCLUSION OCT can allow real-time, non-invasive imaging of artificially bleached tooth models and automatically measure the early changes in the enamel lesion structure upon exposure to hydrogen peroxide-based bleaching agents.
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Affiliation(s)
- Yuhao Yang
- Department of Endodontics, Affiliated Stomatological Hospital, Nanchang University, Nanchang, Jiangxi 330006, China; Jiangxi Key Laboratory of Oral Biomedicine, Nanchang, Jiangxi 330006, China
| | - Qiaoqiao Xue
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, Jiangxi 330063, China
| | - Yubao Zhang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, Jiangxi 330063, China
| | - Xingdao He
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, Jiangxi 330063, China
| | - Zekun Li
- Department of Endodontics, Affiliated Stomatological Hospital, Nanchang University, Nanchang, Jiangxi 330006, China; Jiangxi Key Laboratory of Oral Biomedicine, Nanchang, Jiangxi 330006, China
| | - Jian Yang
- Department of Endodontics, Affiliated Stomatological Hospital, Nanchang University, Nanchang, Jiangxi 330006, China; Jiangxi Key Laboratory of Oral Biomedicine, Nanchang, Jiangxi 330006, China.
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Chang NYN, Dillas T, Zhu Y, Fried D. Assessment of the activity of secondary caries lesions with short-wavelength infrared, thermal, and optical coherence tomographic imaging. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:094801. [PMID: 36761935 PMCID: PMC9830003 DOI: 10.1117/1.jbo.28.9.094801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/15/2022] [Indexed: 06/18/2023]
Abstract
Significance: Leakage in the interfaces between restorative materials and tooth structure allows for fluid and bacterial acid infiltration, causing restoration failure due to secondary caries. Dentists spend more time replacing composite restorations than placing new ones. Previous in vitro and in vivo studies on enamel and root surfaces using shortwave-infrared (SWIR) and thermal imaging during dehydration with forced air have been promising for assessing lesion activity. Aim: We hypothesized that SWIR reflectance and thermal imaging methods can be used to monitor the activity of secondary caries lesions around composite restorations. The objective of this study was to employ these methods to measure the rate of fluid loss from lesions during dehydration with forced air to assess lesion activity. Approach: Sixty-three extracted human teeth with total of 109 suspected secondary lesions were examined using SWIR and thermal imaging during dehydration. The thickness of the highly mineralized transparent surface layer (TSL) at lesion interfaces indicative of lesion activity was measured by optical coherence tomography (OCT). Micro-computed tomography (MicroCT) was used to further confirm lesion severity and structure. OCT and MicroCT measurements of lesion structure, depth, and severity were correlated with fluid loss rates measured with SWIR reflectance and thermal imaging. Results: TSL thickness measured with OCT correlated with both SWIR reflectance and thermal measurements of rates of fluid loss ( p < 0.05 ). Increasing TSL thickness led to decreased permeability of lesions, potentially indicating full lesion arrest at TSL ≥ 70 μ m . SWIR performed better than thermal imaging for secondary lesion activity assessment, although both methods performed best on smooth surface lesions. Conclusions: Nondestructive SWIR reflectance and OCT imaging methods are promising for clinically monitoring the activity of secondary caries lesions.
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Affiliation(s)
- Nai-Yuan N. Chang
- University of California, San Francisco, San Francisco, California, United States
| | - Tina Dillas
- University of California, San Francisco, San Francisco, California, United States
| | - Yihua Zhu
- University of California, San Francisco, San Francisco, California, United States
| | - Daniel Fried
- University of California, San Francisco, San Francisco, California, United States
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Zhu Y, Kim J, Lin B, Fried D. Monitoring lesion activity on primary teeth with CP-OCT and SWIR reflectance imaging. Lasers Surg Med 2023. [PMID: 37172310 DOI: 10.1002/lsm.23677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/03/2023] [Accepted: 05/03/2023] [Indexed: 05/14/2023]
Abstract
OBJECTIVE The purpose of this study was to use cross polarization optical coherence tomography (CP-OCT) and short wavelength infrared imaging (SWIR) reflectance imaging to monitor changes in the structure and activity of early occlusal caries on primary teeth over a period of 6 months during intervention with fluoride. METHODS Participants (n = 29) aged 6-10 each with two suspected active occlusal lesions on primary teeth completed the study. Fluoride varnish was applied to tooth surfaces every 3-months and participants were instructed to brush twice daily with a fluoride toothpaste. Images were acquired using CP-OCT every 3 months for 6 months. SWIR reflectance images were acquired during forced air-drying of the lesions for 30 s at 0 and 6-months. RESULTS Most of the 42 lesions appeared initially active at baseline. Only 6 lesions appeared arrested at baseline based on the presence of a highly mineralized transparent surface layer (TSL) in CP-OCT images. At 6 months, 14 of the lesions appeared arrested including the 6 initially arrested lesions and the TSL thickness increased significantly (p < 0.0001). The mean lesion depth (Ld) and the integrated reflectivity over the lesion depth (ΔR) increased significantly (p < 0.05) after 6 months for the 42 lesions analyzed. SWIR reflectance images showed that there was a significantly higher (p < 0.05) delay before changes in intensity were measured for active lesions versus arrested lesions during lesion drying. CONCLUSION CP-OCT was able to monitor changes in lesion structure and activity including the formation of a highly mineralized TSL indicative of lesion arrest during nonsurgical intervention. Time-resolved SWIR reflectance imaging also shows that there are differences in the dehydration kinetics between active and arrested lesions. This study demonstrates two independent imaging methods that can be used to monitor changes in lesion activity over time.
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Affiliation(s)
- Yihua Zhu
- School of Dentistry, University of California San Francisco, San Francisco, California, USA
| | - Jungsoo Kim
- School of Dentistry, University of California San Francisco, San Francisco, California, USA
| | - Brent Lin
- School of Dentistry, University of California San Francisco, San Francisco, California, USA
| | - Daniel Fried
- School of Dentistry, University of California San Francisco, San Francisco, California, USA
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Zhu Y, Kim M, Curtis D, Wang J, Le O, Fried D. Active Surveillance of Root Caries in Vivo with CP-OCT. Diagnostics (Basel) 2023; 13:diagnostics13030465. [PMID: 36766570 PMCID: PMC9914565 DOI: 10.3390/diagnostics13030465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/19/2023] [Accepted: 01/21/2023] [Indexed: 02/03/2023] Open
Abstract
The active surveillance of root caries lesions to monitor potential remineralization or decay progression is challenging for the clinician, due to unreliable diagnostic information. The conventional visual and tactile methods for assessing the lesion activity are not reliable, and the clinician is often unable to determine if the lesion is progressing or has been arrested. An important marker of an arrested lesion is a highly mineralized transparent surface zone (TSL) that forms when the mineral is deposited in the outer layer of the lesion. The purpose of this study was to determine if cross-polarization optical coherence tomography (CP-OCT) could be used to detect changes in the lesion severity and activity during active monitoring. In total, 18 subjects with 22 suspected active root caries lesions were evaluated using CP-OCT at the baseline, 3 months, and 6 months. All subjects were instructed to use a high fluoride dentifrice at the baseline. The results showed that CP-OCT was able to discriminate the active from the arrested lesions by identifying the presence of a TSL on arrested lesions. The results also indicated that the mean TSL thickness increased significantly (p < 0.05) for the nine lesion areas. In addition, CP-OCT was able to show the progression of demineralization, erosion, and changes in gingival contours in scanned areas. CP-OCT was valuable for monitoring the activity and severity of root caries lesions in vivo. CP-OCT can be used to assess the activity of root caries lesions at a single time point by detecting the presence of a TSL at the lesion surface indicative of the lesion arrest.
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Tang P, Le N, Lu J, Chung KH, Subhash H, Kilpatrick-Liverman L, Wang RK. Local axis orientation mapped by polarization sensitive optical coherence tomography provides a unique contrast to identify caries lesions in enamel. BIOMEDICAL OPTICS EXPRESS 2022; 13:4247-4260. [PMID: 36032575 PMCID: PMC9408248 DOI: 10.1364/boe.464707] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/08/2022] [Accepted: 07/08/2022] [Indexed: 05/11/2023]
Abstract
Due to rod-like hydroxyapatite crystal organizations, dental enamel is optically anisotropic, i.e., birefringent. Healthy enamel is known to be intrinsically negatively birefringent. However, when demineralization of enamel occurs, a considerable number of inter-crystallite spaces would be created between the crystallites in the enamel, which could lead to a sign reversion in birefringence of the enamel structure. We propose that this sign reversion can be leveraged in polarization sensitive OCT (PSOCT) imaging to differentiate early caries lesions from healthy enamel. In this study using PSOCT, we first confirm that the change in birefringence sign (negative to positive) can lead to a 90-degree alteration in the local axis orientation because of the switch between the fast and slow optic axes. We then demonstrate, for the first time, that the local axis orientation can be utilized to map and visualize the WSLs from the healthy enamel with a unique contrast. Moreover, the sharp alteration in local axis orientation gives a clear boundary between the WSLs and the healthy enamel, providing an opportunity to automatically segment the three-dimensional WSLs from the healthy enamel, enabling the characterization of their size and depth information in an intuitive way, which may aid clinical decision making and treatment planning.
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Affiliation(s)
- Peijun Tang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
| | - Nhan Le
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
| | - Jie Lu
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
| | - Kwok-Hung Chung
- Department of Restorative Dentistry, University of Washington, Seattle, WA,98195, USA
| | - Hrebesh Subhash
- Clinical Method Development – Oral Care, Colgate-Palmolive Company, Piscataway, New Jersey, USA
| | | | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
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Tressel J, Kashirtsev F, Cheung K, Simon J, Fried D. Caries inhibition of simulated active caries lesions with CO 2 laser irradiation and fluoride. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2022; 11942:119420B. [PMID: 35450400 PMCID: PMC9020385 DOI: 10.1117/12.2608308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
It has been well established that CO2 laser irradiation can be used to transform the mineral phase of dental enamel to make it more resistant to acid dissolution. The purpose of this study was to investigate if carbon dioxide laser irradiation and topical fluoride can be used to treat incipient caries lesions to inhibit further progression, i.e. treat active lesion surfaces as opposed to sound surfaces prior to subjecting them to an acid challenge. Simulated active caries lesions were produced on twenty eight bovine enamel samples using a pH cycling model and those surfaces were irradiated by a 9.4 μm CO2 laser and treated with topical fluoride. Changes in the surface morphology, acid resistance, and permeability were measured using digital microscopy, optical coherence tomography (OCT), and SWIR reflectance surface dehydration rate measurements at 1950 nm after exposure to a further acid challenge. There was a significant reduction (P < 0.05) of further lesion progression for lesion windows treated with CO2 laser irradiation followed by the application of an acidulated phosphate fluoride gel compared to the untreated lesion windows on each sample. Treatment by laser irradiation alone was not effective. The degree of lesion inhibition was not as high as has been previously observed for laser irradiated sound enamel surfaces exposed to an acid challenge.
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Affiliation(s)
- John Tressel
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Filipp Kashirtsev
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Kevin Cheung
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Jacob Simon
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Daniel Fried
- University of California, San Francisco, San Francisco, CA 94143-0758
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He C, He H, Chang J, Chen B, Ma H, Booth MJ. Polarisation optics for biomedical and clinical applications: a review. LIGHT, SCIENCE & APPLICATIONS 2021; 10:194. [PMID: 34552045 PMCID: PMC8458371 DOI: 10.1038/s41377-021-00639-x] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 05/13/2023]
Abstract
Many polarisation techniques have been harnessed for decades in biological and clinical research, each based upon measurement of the vectorial properties of light or the vectorial transformations imposed on light by objects. Various advanced vector measurement/sensing techniques, physical interpretation methods, and approaches to analyse biomedically relevant information have been developed and harnessed. In this review, we focus mainly on summarising methodologies and applications related to tissue polarimetry, with an emphasis on the adoption of the Stokes-Mueller formalism. Several recent breakthroughs, development trends, and potential multimodal uses in conjunction with other techniques are also presented. The primary goal of the review is to give the reader a general overview in the use of vectorial information that can be obtained by polarisation optics for applications in biomedical and clinical research.
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Affiliation(s)
- Chao He
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK.
| | - Honghui He
- Guangdong Engineering Center of Polarisation Imaging and Sensing Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, China.
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, China.
| | - Jintao Chang
- Guangdong Engineering Center of Polarisation Imaging and Sensing Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, China
- Department of Physics, Tsinghua University, 100084, Beijing, China
| | - Binguo Chen
- Guangdong Engineering Center of Polarisation Imaging and Sensing Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, China
- Department of Biomedical Engineering, Tsinghua University, 100084, Beijing, China
| | - Hui Ma
- Guangdong Engineering Center of Polarisation Imaging and Sensing Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, China
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, China
- Department of Physics, Tsinghua University, 100084, Beijing, China
| | - Martin J Booth
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK.
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Yavuz BS, Kargul B. Comparative evaluation of the spectral-domain optical coherence tomography and microhardness for remineralization of enamel caries lesions. Dent Mater J 2021; 40:1115-1121. [PMID: 33980748 DOI: 10.4012/dmj.2020-279] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study aimed to evaluate the Cirrus high-definition (HD) spectral-domain optical coherence tomography (SD-OCT) for the remineralization of artificial enamel caries and to compare it with the comparison surface microhardness (SMH) analysis. Artificial caries lesions were produced on forty human enamel samples. Then, three different remineralization agents containing casein phosphopeptide amorphous calcium phosphate; casein phosphopeptide amorphous calcium fluoride phosphate; calcium glycerophosphate, magnesium chloride, and xylitol; and remineralization solution (control) were applied with pH cycling for six days. The optical depth of backscattered light and microhardness of enamel were measured using SD-OCT and SMH. All remineralization agents were significantly efficient in reducing optical lesion depth on enamels (p1=0.001, p2=0.002, p3=0.006, p4=0.025), and in increasing the SMH of enamels (p1-3=0.005, p4=0.017). However, the optical lesion depths of the enamel showed no correlation with the SMH in the groups. In conclusion, demineralization and remineralization of artificial lesions can be assessed with both SD-OCT and SMH.
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Affiliation(s)
- Betul Sen Yavuz
- Department of Pediatric Dentistry, School of Dental Medicine, Bahcesehir University
| | - Betul Kargul
- Department of Pediatric Dentistry, School of Dentistry, Marmara University
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Liu H, Chang NY, Gao W, Fried D. Infrared imaging confirms the role of the transparent surface zone in arresting dental caries. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2021; 11627. [PMID: 33767521 DOI: 10.1117/12.2584907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Several studies have demonstrated the potential of short wavelength infrared (SWIR) reflectance, thermal imaging and optical coherence tomography for the nondestructive assessment of the activity of caries lesions. The purpose of this study was to test the hypothesis that the activity of arrested caries lesions on the coronal surfaces of extracted teeth would be changed by reducing the thickness of the highly mineralized transparent surface layer, which was measured using polarization sensitive optical coherence tomography (PS-OCT). The lesion activity was assessed using SWIR reflectance and thermal imaging during forced air drying of the lesion before and after mechanical removal of a surface layer ~ 50-μm thick covering the lesion. Both the intensity change in SWIR reflectance images at 1500-1750-nm wavelengths after drying the lesions and the change in thermal emission measured with a thermal camera at 8-13-μm wavelengths increased significantly (P<0.05) after reducing the thickness of the mineralized surface layer in the lesions indicating the permeability of the lesion to fluids increased. These results provide further evidence that the presence of a highly mineralized outer surface layer is a key indicator of lesion arrest.
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Affiliation(s)
- Hao Liu
- Purple Mountain Laboratories, Nanjing, P. R. China, 211111.,University of California, San Francisco, San Francisco, California, United States, 94143
| | - Nai-Yuan Chang
- University of California, San Francisco, San Francisco, California, United States, 94143
| | - Wanrong Gao
- Nanjing University of Science and Technology, Nanjing, P. R. China, 210094
| | - Daniel Fried
- University of California, San Francisco, San Francisco, California, United States, 94143
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Fried WA, Abdelaziz M, Darling CL, Fried D. High Contrast Reflectance Imaging of Enamel Demineralization and Remineralization at 1950-nm for the Assessment of Lesion Activity. Lasers Surg Med 2021; 53:968-977. [PMID: 33442896 DOI: 10.1002/lsm.23371] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/08/2020] [Accepted: 12/12/2020] [Indexed: 11/12/2022]
Abstract
BACKGROUND AND OBJECTIVES Previous studies have shown that large changes in the diffuse reflectivity of caries lesions during drying with air can be used to assess lesion activity. The largest changes occur at short wavelength infrared (SWIR) wavelengths coincident with high water absorption. The strongest water absorption in the SWIR occurs at 1950 nm. In this study changes in the reflectivity of simulated lesions with varying degrees of remineralization was measured at 1500-2340 nm and at 1950 nm as the samples were dried with air. STUDY DESIGN/MATERIALS AND METHODS Twenty bovine enamel surfaces each with five treatment windows were exposed to two demineralization/remineralization regimens to produce simulated lesions of varying depth, severity, and mineral gradients. An extended range tungsten-halogen lamp with a long pass filter (1500-2340 nm) and a broadband amplified spontaneous emission source centered near the peak of the water-absorption band at 1950-nm were used as light sources and an extended range InGaAs camera (1000-2340 nm) was used to acquire reflected light images as the samples were dried with air. Lesions were also assessed using digital microscopy, polarized light microscopy, optical coherence tomography, and transverse microradiography. RESULTS Both wavelength ranges showed extremely high lesion contrast (>0.9) for all six lesion treatment windows in both models. The change in contrast (ΔI) was significantly higher for the 1950 nm broadband source for all the intact lesion windows compared with the 1500-2340 nm wavelength range. CONCLUSION SWIR light at 1950 nm yields extremely high contrast of demineralization and appears to be the optimum wavelength for the assessment of lesion activity on tooth coronal surfaces. Lasers Surg. Med. 00:00-00, 2020. © 2020 Wiley Periodicals LLC.
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Affiliation(s)
- William A Fried
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California, 94143
| | - Marwa Abdelaziz
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California, 94143
| | - Cynthia L Darling
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California, 94143
| | - Daniel Fried
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California, 94143
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Yang V, Zhu Y, Curtis D, Le O, Chang NYN, Fried WA, Simon JC, Banan P, Darling CL, Fried D. Thermal Imaging of Root Caries In Vivo. J Dent Res 2020; 99:1502-1508. [PMID: 32866422 DOI: 10.1177/0022034520951157] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Improved methods are needed to assess the structure and activity of lesions on root surfaces in order to improve clinical decision making. Conventional visual and tactile methods for assessing lesion activity are not reliable, and the clinician is often unable to evaluate if the lesion is progressing or has remineralized. An important marker of an arrested lesion is a highly mineralized surface zone that forms when mineral is deposited in the outer layer of the lesion. In vitro studies have shown that a mineralized surface zone influences the kinetics of water evaporation and the surface temperature while drying. Temperature changes can be monitored by measuring the thermal emission with thermal imaging. Studies have also shown that the depth and severity of demineralization and the thickness of the highly mineralized transparent surface zone on arrested lesions can be measured nondestructively with optical coherence tomography (OCT). Thermal imaging at 8-µm to 13-µm wavelengths was completed on 30 test subjects with a suspected active root caries lesion by monitoring thermal emission from the tooth surfaces during 30 s of air drying. Lesions were also evaluated using cross-polarization OCT (CP-OCT) during lesion dehydration to identify transparent surface zones indicative of arrested lesions and determine if shrinkage occurred during drying. The overall thermal emission recorded during drying was significantly different (P < 0.001) when comparing sound tooth surfaces, lesion areas identified as arrested, and lesion areas identified as active, demonstrating that thermal imaging is a promising approach for the clinical assessment of lesion activity on root surfaces. Ten of the lesions in this study had distinct areas with transparent surface zones that were visible in CP-OCT images. Shrinkage was detected with CP-OCT during drying for 12 lesions. This study confirms that these novel approaches for assessing lesion activity on root surfaces can be implemented in vivo.
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Affiliation(s)
- V Yang
- University of California, San Francisco, San Francisco, CA, USA
| | - Y Zhu
- University of California, San Francisco, San Francisco, CA, USA
| | - D Curtis
- University of California, San Francisco, San Francisco, CA, USA
| | - O Le
- University of California, San Francisco, San Francisco, CA, USA
| | - N Y N Chang
- University of California, San Francisco, San Francisco, CA, USA
| | - W A Fried
- University of California, San Francisco, San Francisco, CA, USA
| | - J C Simon
- University of California, San Francisco, San Francisco, CA, USA
| | - P Banan
- University of California, San Francisco, San Francisco, CA, USA
| | - C L Darling
- University of California, San Francisco, San Francisco, CA, USA
| | - D Fried
- University of California, San Francisco, San Francisco, CA, USA
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Sahyoun CC, Subhash HM, Peru D, Ellwood RP, Pierce MC. An Experimental Review of Optical Coherence Tomography Systems for Noninvasive Assessment of Hard Dental Tissues. Caries Res 2019; 54:43-54. [PMID: 31533102 DOI: 10.1159/000502375] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 07/26/2019] [Indexed: 11/19/2022] Open
Abstract
Optical coherence tomography (OCT) is a noninvasive, high-resolution, cross-sectional imaging technique. To date, OCT has been demonstrated in several areas of dentistry, primarily using wavelengths around 1,300 nm, low numerical aperture (NA) imaging lenses, and detectors insensitive to the polarization of light. The objective of this study is to compare the performance of three commercially available OCT systems operating with alternative wavelengths, imaging lenses, and detectors for OCT imaging of dental enamel. Spectral-domain (SD) OCT systems with (i) 840 nm (Lumedica, OQ LabScope 1.0), (ii) 1,300 nm (Thorlabs, Tel320) center wavelengths, and (iii) a swept-source (SS) OCT system (Thorlabs OCS1300SS) centered at 1,325 nm with optional polarization-sensitive detection were used. Low NA (0.04) and high NA (0.15) imaging lenses were used with system (iii). Healthy in vivo and in vitrohuman enamel and eroded in vitro bovine enamel specimens were imaged. The Tel320 system achieved greater imaging depth than the OQ LabScope 1.0, on average imaging 2.6 times deeper into the tooth (n = 10). The low NA lens provided a larger field of view and depth of focus, while the high NA lens provided higher lateral resolution and greater contrast. Polarization-sensitive imaging eliminated birefringent banding artifacts that can appear in conventional OCT scans. In summary, this study illustrates the performance of three commercially available OCT systems, objective lenses, and imaging modes and how these can affect imaging depth, resolution, field of view, and contrast in enamel. Users investigating OCT for dental applications should consider these factors when selecting an OCT system for clinical or basic science studies.
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Affiliation(s)
- Christine C Sahyoun
- Department of Biomedical Engineering, Rutgers, the State University of New Jersey, Piscataway, New Jersey, USA
| | - Hrebesh M Subhash
- Global Development Center, Colgate-Palmolive Company, Piscataway, New Jersey, USA
| | - Deborah Peru
- Global Development Center, Colgate-Palmolive Company, Piscataway, New Jersey, USA
| | - Roger P Ellwood
- Global Development Center, Colgate-Palmolive Company, Piscataway, New Jersey, USA
| | - Mark C Pierce
- Department of Biomedical Engineering, Rutgers, the State University of New Jersey, Piscataway, New Jersey, USA,
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15
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Shi W, Chen C, Pasarikovski CR, Gao W, Yang VXD. Differential phase standard-deviation-based optical coherence tomographic angiography for human retinal imaging in vivo. APPLIED OPTICS 2019; 58:3401-3409. [PMID: 31044835 DOI: 10.1364/ao.58.003401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
We present a differential phase standard-deviation (DPSD)-based optical coherence tomographic (OCT) angiography (OCTA) technique to calculate the angiography images of the human retina. The standard deviation was calculated along the depth direction on the differential phase image of two B-scans (from the same position, at different times) to contrast dynamic vascular signals. The performance of a DPSD was verified by both phantom and in vivo experiments. When compared to other OCTA algorithms such as phase variance OCT, speckle variance OCT, and optical microangiography, we showed that a DPSD achieved improved image contrast and higher sensitivity. Furthermore, we also found the improved signal-to-noise ratio and contrast-to-noise ratio of 1.6 dB and 0.5, respectively, in large scanning range images.
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Dhillon N, Chan KH, Yang VB, Fried D. Image guided laser ablation of demineralization from root surfaces. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2019; 10857:108570N. [PMID: 31007338 PMCID: PMC6469870 DOI: 10.1117/12.2512938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
It is challenging to identify demineralized areas of root lesions due to cervical erosion, calculus formation, and heavy staining of dentin. We have found that root caries can be imaged with extremely high contrast at short wavelength IR (SWIR) wavelengths beyond 1500-nm. Lasers are well suited for the selective removal of caries lesions from tooth surfaces. A CO2 laser operating at a wavelength of 9.3-μm was combined with a thulium-doped fiber laser operating at 1880-nm for the selective removal of root caries lesions from extracted teeth. Serial SWIR reflectance images at 1880-nm were used to guide the CO2 laser for image-guided laser ablation. Cross polarization optical coherence tomography (CP-OCT) was used to assess the initial depth of the lesions before removal and assess the volume of sound and demineralized tissue removed by the CO2 laser. With this image-guided approach, we believe we can achieve highly selective lesion removal and minimal damage to surrounding sound tissues.
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Affiliation(s)
| | - Kenneth H Chan
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Vincent B Yang
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Daniel Fried
- University of California, San Francisco, San Francisco, CA 94143-0758
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17
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Abstract
Optical coherence tomography (OCT) is a noninvasive diagnostic technique providing cross-sectional images of biologic structures based on the differences in tissue optical properties. OCT has been widely used in numerous clinical applications and is becoming popular as a promising technology in dentistry. Today, dental hard (tooth) and soft (hard palate mucosa and gingiva mucosa) tissues are visualized with OCT. With new developments in technology, the applications of OCT are being investigated in various fields in dentistry, such as to detect microleakage around restoration, tooth cracks/fractures, examination of periodontal tissues/pockets, early detection of oral cancerous tissues, and in endodontics for location of pulp canal.
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Affiliation(s)
- Rujuta A Katkar
- Department of Comprehensive Dentistry, UT Health, School of Dentistry, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
| | | | - Bennett T Amaechi
- Department of Comprehensive Dentistry, University of Texas Health Science San Antonio, School of Dentistry, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | - Daniel Fried
- Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, 707 Parnassus Avenue, San Francisco, CA 94143-0758, USA
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Bleaching of simulated stained-remineralized caries lesions in vitro. Clin Oral Investig 2018; 23:1785-1792. [PMID: 30182319 DOI: 10.1007/s00784-018-2590-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 08/17/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Non-invasive esthetic treatment options for stained arrested caries lesions have not been explored. This study aimed to develop laboratory models to create stained-remineralized caries-like lesions (s-RCLs) and to test the efficacy of bleaching on their esthetic treatment. MATERIALS AND METHODS One hundred twelve enamel/dentin specimens were prepared from human molars, embedded, and had their color measured spectrophotometrically at baseline and after demineralization. They were randomly divided into four groups (n = 14) based on the staining/remineralization protocols for a total of 5 days: G1, no staining/no remineralization; G2, no staining/remineralization in artificial saliva (AS); G3, non-metallic staining/remineralization with sodium fluoride/AS; and G4, metallic staining/remineralization with silver diamine fluoride/AS. The lesion mineral loss (ΔZ) and depth (L) were measured using transverse microradiography along with color change (ΔE). Specimens were bleached and color was re-evaluated. Data were analyzed using ANOVA models followed by Fisher's PLSD tests (α = 0.05). RESULTS s-RCLs in G4 were significantly (p < 0.001) darker than G3, G2, and G1 regardless of substrate type and condition. s-RCLs in G2, G3, and G4 showed significantly lower ΔZ and L than G1 (all p < 0.001), confirming occurrence of remineralization. G4 exhibited significantly lower ΔZ and L compared to G2 (p < 0.001). Bleaching was more effective in non-metallic than in metallic stained lesions regardless of substrate type (p < 0.001). CONCLUSION The proposed models created distinct s-RCLs. Non-metallic s-RCLs were lighter and more responsive to bleaching compared to metallic s-RCLs. CLINICAL RELEVANCE The developed experimental models allow the further investigation of the efficacy and safety of different clinical strategies for the esthetic management of s-RCLs.
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Chan KH, Fried D. Selective ablation of dental caries using coaxial Co2(9.3-μm) and near-IR (1880-nm) lasers. Lasers Surg Med 2018; 51:176-184. [DOI: 10.1002/lsm.23002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Kenneth H. Chan
- Department of Preventive and Restorative Dental Sciences; University of California, San Francisco; San Francisco 94143-0758 California
| | - Daniel Fried
- Department of Preventive and Restorative Dental Sciences; University of California, San Francisco; San Francisco 94143-0758 California
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20
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Damodaran V, Vasa NJ, Sarathi R. KTN-based high-speed axial and lateral scanning technique for an optical coherence tomography system and application to dental imaging. APPLIED OPTICS 2018; 57:2915-2922. [PMID: 29714295 DOI: 10.1364/ao.57.002915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
A high-speed 840 nm based polarization-sensitive time domain optical coherence tomography (PSOCT) technique is proposed and demonstrated based on the quadratic electro-optic property of potassium tantalate niobate (KTN) crystals. A longitudinal (axial) scanning depth of ≈10 μm is obtained for an applied AC voltage of 600 V, at 1000 Hz and temperature maintained around 40°C. The OCT system with the KTN-based electro-optic delay line combined with a linear actuation is extended to image an early dental demineralization. For enhanced contrast by the elimination of the strong surface reflection from the sample and high-speed imaging, the quadratic electro-optically tunable PSOCT technique is proposed and demonstrated. Further, a lateral scanning range of 490 μm is also demonstrated by controlling the KTN temperature at 35°C for an applied voltage of 600 V on the tooth sample. This KTN-based quadratic electro-optic delay line combined with lateral scan approach provides an automated high-speed two-dimensional scanning of samples of interest.
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21
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Chan KH, Fried NM, Fried D. Selective Ablation of Carious Lesions using an Integrated Near-IR Imaging System and a Novel 9.3-µm CO 2 Laser. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2018; 10473. [PMID: 30034078 DOI: 10.1117/12.2296025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Previous studies have shown that reflectance imaging at wavelengths greater than 1200-nm can be used to image demineralization on tooth occlusal surfaces with high contrast and without the interference of stains. In addition, these near-IR imaging systems can be integrated with laser ablation systems for the selective removal of carious lesions. Higher wavelengths, such as 1950-nm, yield higher lesion contrast due to higher water absorption and lower scattering. In this study, a point-to-point scanning system employing diode and fiber lasers operating at 1450, 1860, 1880, and 1950-nm was used to acquire reflected light images of the tooth surface. Artificial lesions were imaged at these wavelengths to determine the highest lesion contrast. Near-IR images at 1880-nm were used to demarcate lesion areas for subsequent selective carious lesion removal using a new compact air-cooled CO2 laser prototype operating at 9.3-µm. The highest lesion contrast was at 1950-nm and the dual NIR/CO2 laser system selectively removed the simulated lesions with a mean loss of only 12-µm of sound enamel.
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Affiliation(s)
- Kenneth H Chan
- University of California, San Francisco, San Francisco, CA 94143-0758
| | | | - Daniel Fried
- University of California, San Francisco, San Francisco, CA 94143-0758
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Chen Y, Li Z, Nan N, Bu Y, Wang X, Pan L, Wang X. Automatic spectral calibration for polarization-sensitive optical coherence tomography. OPTICS EXPRESS 2017; 25:23605-23618. [PMID: 29041312 DOI: 10.1364/oe.25.023605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Accurate wavelength assignment is important for Fourier domain polarization-sensitive optical coherence tomography. Incorrect wavelength mapping between the orthogonal horizontal (H) and vertical (V) polarization channels leads to broadening the axial point spread function and generating polarization artifacts. To solve the problem, we propose an automatic spectral calibration method by seeking the optimal calibration coefficient between wavenumber kH and kV. The method first performs a rough calibration to get the relationship between the wavelength λ and the pixel number x of the CCD for each channel. And then a precise calibration is taken to bring both polarization interferograms in the same k range through the optimal calibration coefficient. The optimal coefficient is automatically obtained by evaluating the cross-correlation of A-line signals. Simulations and experiments are implemented to demonstrate the performance of the proposed method. The results show that, compared to the peaks method, the proposed method is suitable in both Gaussian and non-Gaussian spectrums with a higher calibration accuracy.
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23
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Polarization Sensitive Optical Coherence Tomography: A Review of Technology and Applications. APPLIED SCIENCES-BASEL 2017. [DOI: 10.3390/app7050474] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Lee RC, Darling CL, Staninec M, Ragadio A, Fried D. Activity assessment of root caries lesions with thermal and near-IR imaging methods. JOURNAL OF BIOPHOTONICS 2017; 10:433-445. [PMID: 27060450 PMCID: PMC5053863 DOI: 10.1002/jbio.201500333] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/08/2016] [Accepted: 03/04/2016] [Indexed: 05/31/2023]
Abstract
The purpose of this study was to evaluate thermal and near-infrared (NIR) reflectance imaging methods for the assessment of the activity of root caries lesions. In addition, changes in the lesion structure were monitored with polarization sensitive optical coherence tomography (PS-OCT). Artificial bovine and natural root caries lesions were imaged with PS-OCT, and their dehydration rate was measured with thermal and NIR cameras. The lesion activity of the natural root caries samples was also assessed by two clinicians by conventional means according to ICDAS II guidelines. The thickness of the highly mineralized transparent surface layer measured using PS-OCT increased and the area enclosed by the time-temperature curve, ΔQ, measured with thermal imaging decreased significantly with longer periods of remineralization in simulated dentin lesions, but the NIR reflectance intensity differences, ΔI, failed to show any significant relationship with the degree of remineralization. The PS-OCT algorithm for the automated assessment of remineralization successfully detected the highly mineralized surface layer on both natural and simulated lesions. Thermal imaging provided the most accurate diagnosis of root caries lesion activity. These results demonstrate that thermal imaging and PS-OCT may be ideally suited for the nondestructive root caries lesion activity during a clinical examination.
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Affiliation(s)
- Robert C. Lee
- Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California 94143-0758
| | - Cynthia L. Darling
- Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California 94143-0758
| | - Michal Staninec
- Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California 94143-0758
| | - Antonio Ragadio
- Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California 94143-0758
| | - Daniel Fried
- Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California 94143-0758
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Kim JM, Kang SR, Yi WJ. Automatic detection of tooth cracks in optical coherence tomography images. J Periodontal Implant Sci 2017; 47:41-50. [PMID: 28261523 PMCID: PMC5332334 DOI: 10.5051/jpis.2017.47.1.41] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/30/2017] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The aims of the present study were to compare the image quality and visibility of tooth cracks between conventional methods and swept-source optical coherence tomography (SS-OCT) and to develop an automatic detection technique for tooth cracks by SS-OCT imaging. METHODS We evaluated SS-OCT with a near-infrared wavelength centered at 1,310 nm over a spectral bandwidth of 100 nm at a rate of 50 kHz as a new diagnostic tool for the detection of tooth cracks. The reliability of the SS-OCT images was verified by comparing the crack lines with those detected using conventional methods. After performing preprocessing of the obtained SS-OCT images to emphasize cracks, an algorithm was developed and verified to detect tooth cracks automatically. RESULTS The detection capability of SS-OCT was superior or comparable to that of trans-illumination, which did not discriminate among the cracks according to depth. Other conventional methods for the detection of tooth cracks did not sense initial cracks with a width of less than 100 μm. However, SS-OCT detected cracks of all sizes, ranging from craze lines to split teeth, and the crack lines were automatically detected in images using the Hough transform. CONCLUSIONS We were able to distinguish structural cracks, craze lines, and split lines in tooth cracks using SS-OCT images, and to automatically detect the position of various cracks in the OCT images. Therefore, the detection capability of SS-OCT images provides a useful diagnostic tool for cracked tooth syndrome.
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Affiliation(s)
- Jun-Min Kim
- Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Se-Ryong Kang
- Department of Biomedical Radiation Sciences, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Korea
| | - Won-Jin Yi
- Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.; Department of Oral and Maxillofacial Radiology, Seoul National University School of Dentistry, Seoul, Korea
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Xiao-Hua D, Hui Y, Xiaoli L, Yanni L, Yingying W, Xiaobin L, Lu X. [Ex vivo assessment of the potency of optical coherence tomography for the detection of early occlusal caries]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2016; 34:564-569. [PMID: 28318154 DOI: 10.7518/hxkq.2016.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE This study aimed to evaluate the potency of optical coherence tomography (OCT) to detect early occlusal caries compared with clinical visual examination. METHODS Approximately 97 sites of occlusal fissures on 77 extracted accessional human teeth were scored by three examiners using conventional visual examination and OCT. Results of histological examination on these sites obtained by polarimicroscope served as a gold standard to analyze the sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV). Results of the area under receiver operating characteristic (ROC) curve (AUC) by visual examination and OCT were also analyzed. The Spearman's rank correlation coefficient with histology and the inter-examiner reliability were compared. RESULTS For sites of enamel demineralization limited to the outer 1/2 of the enamel layer, the detection rate of OCT (14/25) was obviously higher than that of the clinical and visual examination (3/25). SE, SP, PPV and NPV of OCT during diagnosis of the early occlusal caries (0.83, 0.64, 0.87 and 0.57) were higher than that of the visual examination (0.79, 0.60, 0.85 and 0.50). AUC (95%CI) of OCT and the visual examination were 0.737 (0.569-0.822) and 0.696 (0.614-0.859), respectively. No statistically significant difference was observed between the results. Results of OCT correlated well with histology (r=0.559, P<0.05). The inter-examiner reliability of OCT was medium. CONCLUSIONS OCT can accurately detect early occlusal lesions atraumatically with high sensitivity and effectiveness. OCT exhibits the potential of auxiliary clinical diagnosis enhancing detection rate and finally implementing early diagnosis and early intervention of early occlusal lesions in clinical practice.
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Affiliation(s)
- Dai Xiao-Hua
- Experimental Research Center, Tianjin Stomatology Hospital, Tianjin 300041, China
| | - Yao Hui
- Experimental Research Center, Tianjin Stomatology Hospital, Tianjin 300041, China
| | - Lian Xiaoli
- Experimental Research Center, Tianjin Stomatology Hospital, Tianjin 300041, China
| | - Li Yanni
- Experimental Research Center, Tianjin Stomatology Hospital, Tianjin 300041, China
| | - Wang Yingying
- Dept. of Conservative Dentistry and Endodontics, Tianjin Stomatology Hospital, Tianjin 300041, China
| | - Liu Xiaobin
- Dept. of Conservative Dentistry and Endodontics, Tianjin Stomatology Hospital, Tianjin 300041, China
| | - Xing Lu
- Dept. of Conservative Dentistry and Endodontics, Tianjin Stomatology Hospital, Tianjin 300041, China
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Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography. SENSORS 2016; 16:s16101598. [PMID: 27690043 PMCID: PMC5087387 DOI: 10.3390/s16101598] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/19/2016] [Accepted: 09/22/2016] [Indexed: 11/16/2022]
Abstract
An application of spectral domain optical coherence tomography (SD-OCT) was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD) panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast) scanning, while a stable linear motorized translational stage was used for lateral (slow) scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are difficult to observe using visual inspection methods. The rapid inspection enabled by this setup led to the early detection of product defects on the manufacturing line, resulting in a significant improvement in the quality assurance of industrial products.
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28
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Tuchin VV. Polarized light interaction with tissues. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:71114. [PMID: 27121763 DOI: 10.1117/1.jbo.21.7.071114] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/22/2016] [Indexed: 05/02/2023]
Abstract
This tutorial-review introduces the fundamentals of polarized light interaction with biological tissues and presents some of the recent key polarization optical methods that have made possible the quantitative studies essential for biomedical diagnostics. Tissue structures and the corresponding models showing linear and circular birefringence, dichroism, and chirality are analyzed. As the basis for a quantitative description of the interaction of polarized light with tissues, the theory of polarization transfer in a random medium is used. This theory employs the modified transfer equation for Stokes parameters to predict the polarization properties of single- and multiple-scattered optical fields. The near-order of scatterers in tissues is accounted for to provide an adequate description of tissue polarization properties. Biomedical diagnostic techniques based on polarized light detection, including polarization imaging and spectroscopy, amplitude and intensity light scattering matrix measurements, and polarization-sensitive optical coherence tomography are described. Examples of biomedical applications of these techniques for early diagnostics of cataracts, detection of precancer, and prediction of skin disease are presented. The substantial reduction of light scattering multiplicity at tissue optical clearing that leads to a lesser influence of scattering on the measured intrinsic polarization properties of the tissue and allows for more precise quantification of these properties is demonstrated.
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Affiliation(s)
- Valery V Tuchin
- Saratov National Research State University, Research-Educational Institute of Optics and Biophotonics, 83 Astrakhanskaya street, Saratov 410012, RussiabInstitute of Precision Mechanics and Control of Russian Academy of Sciences, 24 Rabochaya street, Sarat
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29
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Lee RC, Staninec M, Le O, Fried D. Infrared Methods for Assessment of the Activity of Natural Enamel Caries Lesions. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2016; 22:6803609. [PMID: 27642246 PMCID: PMC5021449 DOI: 10.1109/jstqe.2016.2542481] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
New diagnostic methods are needed for the accurate assessment of caries lesion activity to establish the need for surgical treatment. Detection of the highly mineralized surface layer that forms near the surface of the lesions as a result of remineralization is important for diagnosis of the lesion activity. Previous studies have demonstrated that novel imaging methods can be used to detect remineralization of artificial enamel caries lesions. In this paper, the activity of natural enamel caries lesions was assessed in-vitro via detection of the surface layer with PS-OCT and dehydration rate measurements with NIR reflectance and thermal imaging modalities. An automated approach for detecting the surface layer with PS-OCT yielded high sensitivity (= 0.79) and high specificity (= 0.93) with moderate correlation (R2 = 0.5920) with histology. Significant differences in dehydration rate measurements were found between the active and the arrested lesions using both the NIR reflectance and thermal imaging modalities. These results demonstrate that these novel imaging methods are ideally suited for nondestructive, noninvasive and quantitative measurement of lesion activity during a single clinical examination in real-time.
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Affiliation(s)
- Robert C. Lee
- Division of Biomaterials and Bioengineering, Department of Preventative and Restorative Dental Sciences, San Francisco School of Dentistry, University of California, San Francisco, CA 94143-0758 USA
| | - Michal Staninec
- Division of Biomaterials and Bioengineering, Department of Preventative and Restorative Dental Sciences, San Francisco School of Dentistry, University of California, San Francisco, CA 94143-0758 USA
| | - Oanh Le
- Division of Biomaterials and Bioengineering, Department of Preventative and Restorative Dental Sciences, San Francisco School of Dentistry, University of California, San Francisco, CA 94143-0758 USA
| | - Daniel Fried
- Division of Biomaterials and Bioengineering, Department of Preventative and Restorative Dental Sciences, San Francisco School of Dentistry, University of California, San Francisco, CA 94143-0758 USA
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Kang H, Darling CL, Fried D. Enhancement of OCT images with vinyl polysiloxane (VPS). PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2016; 9692. [PMID: 27011417 DOI: 10.1117/12.2218649] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Several studies have shown that optical coherence tomography (OCT) can be used to measure the remaining enamel thickness and detect the location of subsurface lesions hidden under the sound enamel. Moreover studies have shown that high refractive index liquids can be used to improve the visibility of subsurface lesions in OCT images. In this study, we demonstrate that vinyl polysiloxane (VPS) impression materials which are routinely used in dentistry can be used to enhance the detection of dentinal lesions on tooth occlusal surfaces. Lesion presence was confirmed with polarized light microscopy and microradiography.
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Affiliation(s)
- Hobin Kang
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Cynthia L Darling
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Daniel Fried
- University of California, San Francisco, San Francisco, CA 94143-0758
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Tom H, Chan KH, Darling CL, Fried D. Near-IR image-guided laser ablation of demineralization on tooth occlusal surfaces. Lasers Surg Med 2016; 48:52-61. [PMID: 26763111 DOI: 10.1002/lsm.22438] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2015] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Studies have shown that reflectance images at near-IR wavelengths coincident with higher water absorption are well-suited for image-guided laser ablation of carious lesions since the contrast between sound and demineralized enamel is extremely high and interference from stains is minimized. The objective of this study was to demonstrate that near-IR reflectance images taken at a wavelength range of 1,500-1,700 nm can be used to guide a 9.3 μm CO(2) laser for the selective ablation of early demineralization on tooth occlusal surfaces. METHODS The occlusal surfaces of ten sound human molars were used in this in vitro study. Shallow simulated caries lesions with random patterns and varying depth and position were produced on tooth occlusal surfaces. Sequential near-IR reflectance images at 1,500-1,700 nm were used to guide the laser for the selective removal of the demineralized enamel. Digital microscopy and polarization sensitive optical coherence tomography (PS-OCT) were used to assess selectivity. RESULTS Images taken before and after lesion removal suggest that the demineralized areas were removed with high selectivity. Although the estimated volume of tissue ablated was typically higher than the initial lesion volume measured with PS-OCT, the volume of enamel removed by the laser correlated well with the initial lesion volume. CONCLUSION Sequential near-IR reflectance images at 1,500-1,700 nm can be used to guide a 9.3 μm CO(2) laser for the selective ablation of early demineralization on tooth occlusal surfaces.
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Affiliation(s)
- Henry Tom
- Department of Preventive and Restorative Dental Science, University of California, San Francisco, California, 94143-0758
| | - Kenneth H Chan
- Department of Preventive and Restorative Dental Science, University of California, San Francisco, California, 94143-0758
| | - Cynthia L Darling
- Department of Preventive and Restorative Dental Science, University of California, San Francisco, California, 94143-0758
| | - Daniel Fried
- Department of Preventive and Restorative Dental Science, University of California, San Francisco, California, 94143-0758
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Dental optical coherence tomography: new potential diagnostic system for cracked-tooth syndrome. Surg Radiol Anat 2015; 38:49-54. [DOI: 10.1007/s00276-015-1514-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/29/2015] [Indexed: 10/23/2022]
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Lee RC, Darling CL, Fried D. Assessment of remineralization via measurement of dehydration rates with thermal and near-IR reflectance imaging. J Dent 2015; 43:1032-42. [PMID: 25862275 DOI: 10.1016/j.jdent.2015.03.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/19/2015] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES Previous studies have demonstrated that the optical changes due to the loss of water from porous lesions can be exploited to assess lesion severity with QLF, thermal and near-IR imaging. Since arrested lesions are less permeable to water due to the highly mineralized surface layer, changes in the rate of water loss can be related to changes in lesion structure. The purpose of this study was to investigate whether the rate of water loss correlates with the degree of remineralization and whether that rate can be measured using thermal and near-IR reflectance imaging. METHODS Artificial bovine enamel lesions (n=30) were prepared by immersion in a demineralization solution for either 8 and 24 h and they were subsequently placed in an acidic remineralization solution for different periods. The samples were dehydrated using an air spray for 30s and surfaces were imaged using a thermal camera and an InGaAs camera at 1300-1700 nm wavelengths. RESULTS The area enclosed by the time-temperature curve, ΔQ, from thermal imaging showed significant differences (P<0.05) between the lesion window and other windows. Near-IR reflectance intensity differences, ΔI, before and after dehydration decreased with longer periods of remineralization. Only near-IR reflectance imaging was capable of detecting significant differences (P<0.05) between the different periods of remineralization. CONCLUSIONS This study demonstrated that both thermal and near-IR reflectance imaging were suitable for the detection of remineralization in simulated caries lesions and near-IR wavelengths longer than 1400 nm are well suited for the assessment of remineralization.
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Affiliation(s)
- Robert C Lee
- University of California, San Francisco, San Francisco, CA 94143-0758, United States
| | - Cynthia L Darling
- University of California, San Francisco, San Francisco, CA 94143-0758, United States
| | - Daniel Fried
- University of California, San Francisco, San Francisco, CA 94143-0758, United States.
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Kang H, Darling CL, Tom H, Fried D. Enhanced detection of dentinal lesions in OCT images using the RKT transformation. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2015; 9306. [PMID: 25914493 DOI: 10.1117/12.2083654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Several studies have shown that optical coherence tomography (OCT) can be used to measure the remaining enamel thickness and detect the location of subsurface lesions hidden under the sound enamel. The purpose of this study was to develop algorithms to enhance the visibility of subsurface structures such as hidden occlusal lesions and the dentinal-enamel junction. Extracted teeth with natural occlusal lesions were imaged with OCT with and without added high index fluids. A Rotating Kernel Transformation (RKT) nonlinear image processing filter was applied to PS-OCT images to enhance the visibility of the subsurface lesions under the sound enamel. The filter significantly increased (P<0.05) the visibility of the subsurface lesions.
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Affiliation(s)
- Hobin Kang
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Cynthia L Darling
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Henry Tom
- University of California, San Francisco, San Francisco, CA 94143-0758
| | - Daniel Fried
- University of California, San Francisco, San Francisco, CA 94143-0758
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IBUSUKI T, KITASAKO Y, SADR A, SHIMADA Y, SUMI Y, TAGAMI J. Observation of white spot lesions using swept source optical coherence tomography (SS-OCT): in vitro and in vivo study. Dent Mater J 2015; 34:545-52. [DOI: 10.4012/dmj.2015-058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Takahide IBUSUKI
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Yuichi KITASAKO
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Alireza SADR
- University of Washington, School of Dentistry
- Tokyo Medical and Dental University, International Exchange Center
| | - Yasushi SHIMADA
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Yasunori SUMI
- Department for Advanced Dental Research Center of Advanced Medicine for Dental and Oral Disease, National Center for Geriatrics and Gerontology
| | - Junji TAGAMI
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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