In Vitro Examination of Secondary Caries Using Infrared Photothermal Radiometry and Modulated Luminescence (original) (raw)

Detection of Dental Secondary Caries Using Frequency-Domain Infrared Photothermal Radiometry (PTR) and Modulated Luminescence (LUM)

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.

Interproximal dental caries detection using Photothermal Radiometry (PTR) and Modulated Luminescence (LUM)

The European Physical …, 2008

Frequency-domain photothermal radiometry (FD-PTR or PTR) has been used to detect mechanical holes and demineralized enamel in the interproximal contact area of extracted human teeth. Thirty four teeth were used in a series of experiments. Preliminary tests to detect mechanical holes created by dental burs and 37% phosphoric acid etching for 20 s on the interproximal contact points showed distinct differences in the signal. Interproximal contact areas were demineralized by using a partially saturated acidic buffer system. Each sample pair was examined with PTR before and after micro-machining or treating at sequential treatment periods spanning 6 hours to 30 days. Dental bitewing radio graphs showed no sign of demineralized lesion even for samples treated for 30 days. µ-CT, TMR and SEM analyses were performed. Although µ-CT and TMR measured mineral losses and lesion depths, only SEM surface images showed visible signs of treatment because of the minimal extent of the demineralization. However, the PTR amplitude increased by more than 300% after 80 hours of treatment. Therefore, PTR has been shown to have sufficient contrast for the detection of very early interproximal demineralized lesions. The technique further exhibited excellent signal reproducibility and consistent signal changes in the presence of interproximal demineralized lesions, attributes which render PTR a reliable probe to detect early interproximal demineralization lesions. Modulated luminescence was also measured simultaneously, but it showed a lower ability to detect these interproximal demineralized lesions than PTR.

Dental depth profilometry using simultaneous frequency-domain infrared photothermal radiometry and laser luminescence for the diagnosis of dental caries

BiOS 2001 The …, 2001

Frequency-domain infrared photothermal radiometry is introduced as a dynamic dental diagnostic tool and its main features are compared with modulated laser luminescence for quantifying sound and carious enamel or dentin. Dental caries found in the fissures or grooves of teeth is very difficult to diagnose or quantify with the present clinical techniques. Visual examination and dental radiographs do not detect the presence of decay until there has been significant carious destruction of the tooth. 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, was developed. 1 Following optical absorption of laser photons, the new set-up can monitor simultaneously and independently the non-radiative (optical-to-thermal) conversion (infrared photothermal radiometry), and the radiative de-excitation (luminescence emission) in turbid media such as hard dental tissue.

Multi-Centre Clinical Evaluation of Photothermal Radiometry and Luminescence Correlated with International Benchmarks for Caries Detection

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.

Dental depth profilometric diagnosis of pit & fissure caries using frequency-domain infrared photothermal radiometry and modulated laser luminescence

Journal de Physique IV (Proceedings), 2005

Non-intrusive, non-contacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with 659-nm and 830-nm laser sources to detect artificial and natural sub-surface defects in human teeth. Fifty-two human teeth were examined with simultaneous measurements of PTR and LUM and compared to conventional diagnostic methods including continuous (dc) luminescence (DIAGNOdent), visual inspection and radiographs by calculating sensitivities and specificities. With the combined criteria of four PTR and LUM signals (two amplitudes and two phases), it was found that the sensitivity of this method was much higher than any of the other methods used in this study, whereas the specificity was comparable to that of dc luminescence diagnostics. Therefore, PTR and LUM, used together as a combined technique, have the potential to be a reliable tool to diagnose early pit and fissure caries and could provide detailed information about deep lesions with its depth profilometric character. Also, from experiments with natural or artificial defects, some depth profilometric characteristics were confirmed.

Dental depth profilometric diagnosis of pit and fissure caries using frequency-domain infrared photothermal radiometry and modulated laser luminescence

Biomedical …, 2004

Non-intrusive, non-contacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with 659-nm and 830-nm laser sources to detect artificial and natural sub-surface defects in human teeth. Fifty-two human teeth were examined with simultaneous measurements of PTR and LUM and compared to conventional diagnostic methods including continuous (dc) luminescence (DIAGNOdent), visual inspection and radiographs by calculating sensitivities and specificities. With the combined criteria of four PTR and LUM signals (two amplitudes and two phases), it was found that the sensitivity of this method was much higher than any of the other methods used in this study, whereas the specificity was comparable to that of dc luminescence diagnostics. Therefore, PTR and LUM, used together as a combined technique, have the potential to be a reliable tool to diagnose early pit and fissure caries and could provide detailed information about deep lesions with its depth profilometric character. Also, from experiments with natural or artificial defects, some depth profilometric characteristics were confirmed.

Quantitative evaluation of the kinetics of human enamel simulated caries using photothermal radiometry and modulated luminescence

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 depth profilometric diagnosis of pit & fissure caries using frequency-domain infrared photothermal radiometry and modulated laser luminescence

Journal de physique, 2005

Non-intrusive, non-contacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with a 659-nm laser source to assess the pits and fissures on the occlusal surfaces of human teeth. Fifty-two human teeth were examined with simultaneous measurements of PTR and LUM and compared to conventional diagnostic methods including continuous (dc) luminescence (DIAGNOdent), visual inspection, and radiographs. To compare each method, sensitivities and specificities were calculated by using histological observations as the gold standard. With the combined criteria of 4 PTR and LUM signals (2 amplitudes and 2 phases), it was found that the sensitivity of this method was much higher than any of the other methods used in this study; whereas, the specificity was comparable to that of dc luminescence diagnostics. Therefore, PTR and LUM, as a combined technique, has the potential to be a reliable tool to diagnose early pit and fissure caries and could provide detailed information about deep lesions with its depth profilometric character.