Interproximal dental caries detection using Photothermal Radiometry (PTR) and Modulated Luminescence (LUM) (original) (raw)
Related papers
Journal of Physics: Conference Series, 2010
Dental caries involves continuous challenges of acid-induced mineral loss and a counteracting process of mineral recovery. As an emerging non-destructive methodology, photothermal radiometry and modulated luminescence (PTR-LUM) has shown promise in measuring changes in tooth mineral content. Human molars (n=37) were subjected to demineralization in acid gel (pH 4.5, 10 days), followed by incubation in remineralisation solutions (pH 6.7, 4 weeks) without or with fluoride (1 or 1000 ppm). PTR-LUM frequency scans (1 Hz -1 kHz) were performed prior to and during demineralization and remineralization treatments. Transverse Micro-Radiography (TMR) analysis followed at treatment conclusion. The non-fluoridated group exhibited opposite amplitude and phase trends to those of the highly fluoridated group: smaller phase lag and larger amplitude. These results point to a complex interplay between surface and subsurface processes during remineralization, confining the thermal-wave centroid toward the dominating layer.
2012
Dental secondary caries is the carious lesion developed around existing restoration margins. Many new technologies have been developed for caries detection purposes, but their performance is unsatisfactory for the specific purpose of secondary caries diagnosis. Therefore, the development of a novel technology to detect secondary caries has been highly necessary. The objective of this research was to investigate the ability of photothermal radiometry and modulated luminescence to detect secondary caries: wall lesions and outer lesions. Changes in experimental PTR-LUM signals due to sequential demineralization on vertical walls of sectioned tooth samples were investigated. Another study was conducted to investigate how two different types of secondary caries, wall lesions and outer lesions, affect the PTR-LUM signals. The studies demonstrated that PTR-LUM is sensitive to progressive demineralization and remineralization on vertical walls of sectioned tooth samples, as well as to the presence of wall lesions and outer lesions developed around composite restorations.
International Journal of …, 2012
The ability of frequency-domain photothermal radiometry (PTR) and modulated luminescence (LUM) to detect secondary caries is presented. Signal behavior upon sequential demineralization and remineralization of a spot (diameter ∼1 mm) on a vertical wall of sectioned tooth samples was investigated experimentally. From these studies, it was found that PTR-LUM signals change, showing a certain pattern upon progressive demineralization and remineralization. PTR amplitudes slightly decreased upon progressive demineralization and slightly increased upon subsequent remineralization. The PTR phase increased during both demineralization and remineralization. LUM amplitudes exhibit a decreasing trend at excitation/probe distances larger than 200 µm away from the edge for both demineralization and remineralization; however, at locations close to the edge (up to ∼200 µm), LUM signals slightly decrease upon demineralization and slightly increase during subsequent remineralization.
Open Dentistry Journal, 2017
Introduction: A clinical study was initiated to investigate a caries detection device (The Canary System (CS)), based on photothermal radiometry and modulated luminescence (PTR-LUM). The primary objective of this study was to determine if PTR-LUM values (in the form of Canary Numbers; CN) correlate with International Caries Diagnostic and Assessment System (ICDAS II) scores and clinical situations. The secondary objectives of this study were to monitor the safety of PTR-LUM, and collect data to determine how CN values could be used to differentiate healthy from decayed tooth surfaces on a normalized scale. Methods: The trial was a four site, non-blinded study. Data was collected from 92 patients, resulting in 842 scanned tooth surfaces over multiple appointments. Surfaces were assessed according to ICDAS II, and further stratified into five clinical situation categories: 1) healthy surface, 2) non-cavitated white and/or brown spots; 3) caries lesions; 4) cavitation and 5) teeth undergoing remineralization therapy. CN data was analyzed separately for smooth and occlusal surfaces. Using a semi-logarithmic graph to plot raw CN (rCN) and normalized (CN) values, rCN data was normalized into a scale of 0-100. Results: Linear correlations (R 2) between CN and ICDAS II groupings for smooth and occlusal surfaces were calculated as 0.9759 and 0.9267, respectively. The mean CN values derived from smooth (20.2±0.6) and occlusal (19±1.0) surfaces identified as healthy had The Open Dentistry Journal, 2017, Volume 11 637 significantly lower CN values (P<0.05) compared with the values from the other clinical situation categories. No adverse events were reported. Conclusion: The present study demonstrated the safety of PTR-LUM for clinical application and its ability to distinguish sound from carious tooth surfaces. A clear shift from the baseline in both PTR and LUM in carious enamel was observed depending on the type and nature of the lesion, and correlated to ICDAS II classification codes, which enabled the preliminary development of a Canary Scale.
Journal of Biomedical Optics, 2011
Photothermal radiometry and modulated luminescence (PTR-LUM) is an emerging nondestructive methodology applied toward the characterization and quantification of dental caries. We evaluate the efficacy of PTR-LUM in vitro to detect, monitor, and quantify human enamel caries. Artificial caries are created in extracted human molars (n = 15) using an acidified gel system (pH 4.5) for 10 or 40 days. PTR-LUM frequency scans (1 Hz-1 kHz) are performed before and during demineralization. Transverse microradiography (TMR) analysis, the current gold standard, follows at treatment conclusion to determine the mineral loss and depth of the artificially demineralized lesions. A theoretical model is applied to PTR experimental data to evaluate the changes in optothermophysical properties of demineralized enamel as a function of time. Higher optical scattering coefficients and poorer thermophysical properties are characteristic of the growing demineralized lesions, as verified by TMR, where the generated microporosities of the subsurface lesion confine the thermal-wave centroid. Enhanced optical scattering coefficients of demineralized lesions result in poorer luminescence yield due to scattering of both incident and converted luminescent photons. PTR-LUM sensitivity to changes in tooth mineralization coupled with opto-thermophysical property extraction illustrates the technique's potential for nondestructive quantification of enamel caries. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).
Dental Dynamic Diagnostics using Simultaneous Frequency-domain PTR and Laser Luminescence
Anal. Sci, 2000
Frequency-domain infrared photothermal radiometry is introduced as a dynamic dental diagnostic tool complimentary to laser luminescence for quantifying sound and defective enamel or dentin. A high-spatial-resolution dynamic experimental imaging set-up, which can provide simultaneous measurements of laser-induced frequency-domain infrared photothermal radiometric and luminescence signals from defects in teeth, has been developed. . . . 1 Following optical absorption of laser photons, the new set-up can monitor simultaneously and independently the non-radiative (optical-to-thermal) conversion via infrared photothermal radiometry; and the radiative de-excitation via luminescence emission. In addition, the optical properties of enamel are determined using a three-dimensional luminescence and photothermal model.
2010
Detection modalities that can evaluate the early stages of dental caries are indispensable. The purpose of this thesis is to evaluate the efficacy of photothermal radiometry and modulated luminescence (PTR-LUM) to non-destructively detect and quantify simulated enamel caries. Two experiments were performed based on the PTR-LUM detection mode: back-propagation or transmission-mode. Artificial demineralized lesions were created in human molars and a subset was further exposed to an artificial remineralizing solution. PTR-LUM frequency scans were performed periodically during de/re-mineralization treatments. PTR data was fitted to a theoretical model based on optical and thermal fluxes in enamel to extract opto-thermophysical parameters. Lesion validation was performed using transverse microradiography (TMR). Optical and thermal properties changed with the development and repair of the caries lesions while theory-derived thicknesses paralleled those determined microradiographically. These trends coupled with the uniqueness-of-fit of the generated parameters illustrate the efficacy of PTR-LUM to non-destructively detect and quantify de/re-mineralized lesions. III Acknowledgements I would like to thank all the lab members at the Center for Advanced Diffusion-Wave Technologies (CADIFT) and Quantum Dental Technologies (QDT) for their insight and support. Specifically, I would like to acknowledge Dr. Raymond Jeon, Dr. Anna Matvienko and Dr. Koneswaran Sivagurunathan for their invaluable assistance, lengthy discussions, suggestions and guidance over the years. Thank you to Dr. Stephen Abrams for his endless motivation and clinical insight into the application and development of caries detection aids. His clinical expertise and knowledge of dental economics are truly invaluable to the dental profession as he continually tries to promote a shift from the traditional-drill, fill and bill‖ approach to dentistry. I would like to express my sincere gratitude toward my supervisors, Dr. Andreas Mandelis and Dr. Yoav Finer for their endless support, leadership and expertise. Thank you to my advisory committee member, Dr. Paul Santerre, for his support and discussions. Thank you to Prof. Mandelis, whose scientific knowledge, perspicacity and motivation made this research project possible and inspired me to meticulously explore the interminable world of quantitative, nondestructive science. I would also like to thank Dr. Bennett Amaechi at the University of Texas Health Science Center at San Antonio for transverse microradiography analysis and his invaluable discussions relating to the experimental protocol and principles of cariology. I would like to acknowledge the following funding agencies for financial support: the Ministry of Research and Innovation (MRI), the Ontario Premier's Discovery Award, the Ontario Research Fund from the Canadian Foundation for Innovation (CFI-ORF) and lastly the Natural Sciences and Engineering Research Council of Canada (NSERC).