Accuracy of different approaches for detecting proximal root caries lesions in vitro.

OBJECTIVES: The objective was to evaluate the diagnostic accuracy of radiographic evaluation (XR), visual-tactile assessment (VT), laser-fluorescence (LF) (DIAGNOdent Pen/KaVo), and near-infrared-light transillumination (NILT) (DIAGNOcam/KaVo) on proximal root caries lesions in vitro. METHODS: Two-hundred extracted permanent premolars and molars with and without proximal root caries lesions were allocated to 50 diagnostic models simulating the proximal contacts between teeth and mounted in a phantom dummy head. Two independent examiners used the diagnostic approaches to detect any or advanced root caries lesions, with histologic evaluation of the lesions serving as reference. Receiver operating characteristic (ROC) curves were employed, and sensitivity, specificity, and the area under the ROC curve (AUC) are calculated. Significant differences in mean AUCs between approaches were assumed if p < 0.05 (two-sample t-test). RESULTS: NILT was not applicable for proximal root caries detection. The sensitivity/specificity to detect any lesions was 0.81/0.63 for XR, 0.76/0.88 for VT and 0.81/0.95 for LF, and the sensitivity/specificity to detect advanced lesions was 0.43/0.94 for XR, 0.66/0.99 for VT, and 0.83/0.78 for LF, respectively. For both, any and advanced root caries lesions, mean AUCs for LF and VT were significantly higher compared to XR (p < 0.05). For any root caries lesions, LF was significantly more accurate than VT (p = 0.01), but not for advanced root caries lesions (p = 0.59). CONCLUSIONS: Under the in vitro conditions chosen, LF and VT were more accurate than XR to detect proximal root caries lesions, with LF being particularly useful for initial lesion stages. CLINICAL RELEVANCE: LF might be a useful diagnostic aid for proximal root caries diagnosis. Clinical studies are necessary to corroborate the findings.

La laserfluorescencia cualitativa en el diagnóstico del límite cavitario

Introducción: La fluorescencia inducida por láser es capaz de discernir entre tejido sano o enfermo y ha sido aplicada a distintos ámbitos dentro de la Odontología. Sin embargo, la laserfluorescencia cualitativa ha sido poco estudiada para determinar el límite cavitario. Objetivo: Evaluar la efectividad y seguridad del uso de la laser-fluorescencia, a λ=450 nm y 405 nm, en la detección del límite cavitario. Método: Se seleccionaron 45 dientes ex-vivo, que presentaban al menos una localización de caries dentinaria. Se determinaron 83 áreas para el estudio en las que se midió la fluorescencia mediante tres sistemas con diferentes longitudes de onda (405-450 nm). Se calculó la seguridad de la prueba con las categorías de color recomendadas por el fabricante y una escala resultado de la recodificación de las variables. Mediante el software Pilxelmator MAC se convirtieron las variables RGB del color en valores cuantitativos de la escala CIE. Los datos fueron introducidos en el programa estadístico SPSS 19.0. Se aplicaron pruebas de significación (α≤0,05). Resultados: Las categorías de color recomendadas por el fabricante no coinciden con las escalas que muestran la mejor sensibilidad y especificidad. La laserfluorescencia (405 nm-450 nm) es más específica que sensible. Las variables L*a*b son capaces de diferenciar entre dentina recuperable y no recuperable y la LIF-405 nm discrimina entre las capas que delimitan el límite cavitario. Conclusiones: La fluorescencia inducida por láser es un método útil para el diagnóstico del límite cavitario, si bien las recomendaciones del fabricante deben ser modificadas. El sistema L*a*b puede contribuir a eliminar la subjetividad del operador.

Introduction: Laser-induced fluorescence is capable of discerning between healthy and diseased tissue and has been applied to different areas within Dentistry. However, qualitative laserfluorescence has been little studied to determine the cavity limit. Objective: To evaluate the effectiveness and safety of the use of laser fluorescence, at λ=450 nm and 405 nm, in detecting the cavity limit. Method: 45 teeth were selected ex-vivo, which presented at least one location of dentin caries. 83 areas were determined for the study in which fluorescence was measured using three systems with different wavelengths (405-450 nm). The safety of the test was calculated with the color categories recommended by the manufacturer and a scale resulting from the recoding of the variables. Using the Pilxelmator MAC software, the RGB color variables were converted into quantitative values of the CIE scale. The data were entered into the SPSS 19.0 statistical program. Significance tests were applied (α≤0.05). Results: The color categories recommended by the manufacturer do not match the scales that show the best sensitivity and specificity. Laserfluorescence (405 nm-450 nm) is more specific than sensitive. The L*a*b variables are capable of differentiating between recoverable and non-recoverable dentin and the LIF-405 nm discriminates between the layers that delimit the cavity boundary. Conclusions: Laser-induced fluorescence is a useful method for diagnosing the cavity limit, although the manufacturer's recommendations must be modified. The L*a*b system can help eliminate operator subjectivity.

Introdução: A fluorescência induzida por laser é capaz de discernir entre tecido saudável e doente e tem sido aplicada em diversas áreas da Odontologia. Entretanto, a laserfluorescência qualitativa tem sido pouco estudada para determinar o limite da cavidade. Objetivo: Avaliar a eficácia e segurança do uso da fluorescência do laser, em λ=450 nm e 405 nm, na detecção do limite da cavidade. Método: Foram selecionados 45 dentes ex-vivo, que apresentavam pelo menos uma localização de cárie dentinária. Foram determinadas 83 áreas para o estudo nas quais a fluorescência foi medida usando três sistemas com diferentes comprimentos de onda (405-450 nm). A segurança do teste foi calculada com as categorias de cores recomendadas pelo fabricante e uma escala resultante da recodificação das variáveis. Utilizando o software Pilxelmator MAC, as variáveis de cores RGB foram convertidas em valores quantitativos da escala CIE. Os dados foram digitados no programa estatístico SPSS 19.0. Foram aplicados testes de significância (α≤0,05). Resultados: As categorias de cores recomendadas pelo fabricante não correspondem às escalas que apresentam melhor sensibilidade e especificidade. A laserfluorescência (405 nm - 450 nm) é mais específica do que sensível. As variáveis L*a*b são capazes de diferenciar entre dentina recuperável e não recuperável e o LIF-405 nm discrimina entre as camadas que delimitam o limite da cavidade. Conclusões: A fluorescência induzida por laser é um método útil para diagnosticar o limite da cavidade, embora as recomendações do fabricante devam ser modificadas. O sistema L*a*b pode ajudar a eliminar a subjetividade do operador.

Methods for the analysis of uranium aerosol concentration in the workplace of uranium processing and fuel fabrication facilities / 中国辐射卫生

Objective To establish a method for uranium aerosol sample collection, dry ashing treatment, and laboratory laser-fluorescence measurement in the workplace of uranium processing and fuel fabrication facilities. Methods Through optimization experiments, the effects of sampling flow, sample pH value, and test temperature on uranium aerosol concentration results were studied, and the detection limit, precision, and recovery rate of the method were tested. Results Under the optimal test conditions, the detection limit of the method was 0.025 ng/mL; the minimum detectable concentration of 1 m3 of aerosol samples was 1.25 × 10−3 μg/m3; the relative standard deviation (RSD) of the measurement results was less than 5%; the recovery rate was between 96% and 104%. Conclusion The detection limit, precision, and accuracy of the method meet the testing requirements for uranium aerosol samples in the workplace of uranium processing and fuel fabrication facilities.

Comparison of novel and established caries diagnostic methods: a clinical study on occlusal surfaces.

BACKGROUND: The purpose of this prospective clinical diagnostic study with validation was to compare the diagnostic accuracy of near-infrared transillumination (NIRT), laser fluorescence measurement (LF), alternating current impedance spectroscopy (ACIS) and their combinations as adjunct methods to visual examination (VE) for occlusal caries detection using a hybrid reference standard. METHODS: Ninety-six first and second non-cavitated permanent molars from 76 individuals (mean age 24.2) were investigated using (VE) (ICDAS) and bitewing radiography (BWR), as well as NIRT, LF and ACIS. The findings of BWR and NIRT were evaluated by two examiners while the other examinations were conducted by one calibrated dentist. The hybrid reference standard consisted of non-operative validation based on the results of VE and BWR and operative validation. Statistical analysis included cross-tabulations, calculation of sensitivity, specificity and area under the receiver operating characteristic curve at three diagnostic thresholds: caries in general, enamel caries and dentin caries. RESULTS: NIRT, LF and ACIS exhibited high sensitivity for caries in general [1.00 (1.00-1.00), 0.77 (0.65-0.88), 0.75 (0.63-0.87)) and for dentin caries (0.97 (0.91-1.03), 0.76 (0.76-0.90), 0.64 (0.47-0.80)]. Sensitivity values for enamel caries were weak (0.21, 0.11, 0.37). Specificity values did not fall below 0.65 (NIRT) for all categories and methods, except for NIRT at the caries detection threshold (0.27). A combination of LF and ACIS with VE improved the diagnostic performance at the overall and the enamel caries threshold. The other methods showed fair to excellent discrimination at the overall caries threshold (NIRT 0.64, LF 0.89 and ACIS 0.86) and acceptable discrimination at the dentin caries threshold (NIRT 0.82, LF 0.81 and ACIS 0.79). AUROC for enamel caries exhibited the weakest discrimination. Accuracy was 65.6% for VE, 69.8% for BWR, 50.0% for NIRT, 53.1% for LF and 74.0% for ACIS. Reliability assessment for BWR and NIRT showed at least substantial agreements for all analyses. CONCLUSIONS: The methods, NIRT, LF and ACIS, revealed different potential but no impeccable performance for occlusal caries detection. All are suitable instruments to detect hidden carious lesion in dentin. As auxiliaries to VE, LF and ACIS showed an increase in diagnostic performance.