scholarly journals Caries Detection Methods Based on Changes in Optical Properties between Healthy and Carious Tissue

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Lena Karlsson
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Developmental Stages ◽  
Early Stage ◽  
Detection Methods ◽  
Caries Detection ◽  
Semiquantitative Assessment ◽  
Invasive Approach ◽  
Tooth Structure ◽  
Objective Evidence

A conservative, noninvasive or minimally invasive approach to clinical management of dental caries requires diagnostic techniques capable of detecting and quantifying lesions at an early stage, when progression can be arrested or reversed. Objective evidence of initiation of the disease can be detected in the form of distinct changes in the optical properties of the affected tooth structure. Caries detection methods based on changes in a specific optical property are collectively referred to as optically based methods. This paper presents a simple overview of the feasibility of three such technologies for quantitative or semiquantitative assessment of caries lesions. Two of the techniques are well-established: quantitative light-induced fluorescence, which is used primarily in caries research, and laser-induced fluorescence, a commercially available method used in clinical dental practice. The third technique, based on near-infrared transillumination of dental enamel is in the developmental stages.

scholarly journals Caries Detection with Near-Infrared Transillumination Using Deep Learning

2019 ◽  
Vol 98 (11) ◽  
pp. 1227-1233 ◽  
Author(s):  
F. Casalegno ◽  
T. Newton ◽  
R. Daher ◽  
M. Abdelaziz ◽  
A. Lodi-Rizzini ◽  
...  
Keyword(s):  
Deep Learning ◽  
Near Infrared ◽  
Early Stage ◽  
Characteristic Curve ◽  
Class Imbalance ◽  
Training Data ◽  
Caries Detection ◽  
Carious Lesions ◽  
Dental Practitioners ◽  
Segmentation Task

Dental caries is the most prevalent chronic condition worldwide. Early detection can significantly improve treatment outcomes and reduce the need for invasive procedures. Recently, near-infrared transillumination (TI) imaging has been shown to be effective for the detection of early stage lesions. In this work, we present a deep learning model for the automated detection and localization of dental lesions in TI images. Our method is based on a convolutional neural network (CNN) trained on a semantic segmentation task. We use various strategies to mitigate issues related to training data scarcity, class imbalance, and overfitting. With only 185 training samples, our model achieved an overall mean intersection-over-union (IOU) score of 72.7% on a 5-class segmentation task and specifically an IOU score of 49.5% and 49.0% for proximal and occlusal carious lesions, respectively. In addition, we constructed a simplified task, in which regions of interest were evaluated for the binary presence or absence of carious lesions. For this task, our model achieved an area under the receiver operating characteristic curve of 83.6% and 85.6% for occlusal and proximal lesions, respectively. Our work demonstrates that a deep learning approach for the analysis of dental images holds promise for increasing the speed and accuracy of caries detection, supporting the diagnoses of dental practitioners, and improving patient outcomes.

Prostate Cancer: Biology, Incidence, Detection Methods, Treatment Methods, and Vaccines

2020 ◽  
Vol 20 (10) ◽  
pp. 847-854
Author(s):  
Ronald Bartzatt
Keyword(s):  
Prostate Cancer ◽  
Cancer Treatment ◽  
Prostate Specific Antigen ◽  
Cancer Biology ◽  
Early Stage ◽  
Specific Antigen ◽  
Detection Methods ◽  
Hormone Refractory Prostate Cancer ◽  
High Risk Prostate Cancer ◽  
Hormone Refractory

Cancer of the prostate are cancers in which most incidences are slow-growing, and in the U.S., a record of 1.2 million new cases of prostate cancer occurred in 2018. The rates of this type of cancer have been increasing in developing nations. The risk factors for prostate cancer include age, family history, and obesity. It is believed that the rate of prostate cancer is correlated with the Western diet. Various advances in methods of radiotherapy have contributed to lowering morbidity. Therapy for hormone- refractory prostate cancer is making progress, for almost all men with metastases will proceed to hormone-refractory prostate cancer. Smoking cigarettes along with the presence of prostate cancer has been shown to cause a higher risk of mortality in prostate cancer. The serious outcome of incontinence and erectile dysfunction result from the cancer treatment of surgery and radiation, particularly for prostate- specific antigen detected cancers that will not cause morbidity or mortality. Families of patients, as well as patients, are profoundly affected following the diagnosis of prostate cancer. Poor communication between spouses during prostate cancer increases the risk for poor adjustment to prostate cancer. The use of serum prostate-specific antigen to screen for prostate cancer has led to a greater detection, in its early stage, of this cancer. Prostate cancer is the most common malignancy in American men, accounting for more than 29% of all diagnosed cancers and about 13% of all cancer deaths. A shortened course of hormonal therapy with docetaxel following radical prostatectomy (or radiation therapy) for high-risk prostate cancer has been shown to be both safe and feasible. Patients treated with docetaxel-estramustine had a prostate-specific antigen response decline of at least 50%. Cancer vaccines are an immune-based cancer treatment that may provide the promise of a non-toxic but efficacious therapeutic alternative for cancer patients. Further studies will elucidate improved methods of detection and treatment.

scholarly journals The Effect of Nitrogen Incorporation on the Optical Properties of Si-Rich a-SiCx Films Deposited by VHF PECVD

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 637
Author(s):  
Hongliang Li ◽  
Zewen Lin ◽  
Yanqing Guo ◽  
Jie Song ◽  
Rui Huang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Chemical Vapor ◽  
Wide Bandgap ◽  
Nonradiative Recombination ◽  
Very High Frequency ◽  
N Content ◽  
High Frequency Plasma ◽  
Frequency Plasma ◽  
N Incorporation

The influence of N incorporation on the optical properties of Si-rich a-SiCx films deposited by very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) was investigated. The increase in N content in the films was found to cause a remarkable enhancement in photoluminescence (PL). Relative to the sample without N incorporation, the sample incorporated with 33% N showed a 22-fold improvement in PL. As the N content increased, the PL band gradually blueshifted from the near-infrared to the blue region, and the optical bandgap increased from 2.3 eV to 5.0 eV. The enhancement of PL was suggested mainly from the effective passivation of N to the nonradiative recombination centers in the samples. Given the strong PL and wide bandgap of the N incorporated samples, they were used to further design an anti-counterfeiting label.

scholarly journals Diagnostic Value of Fluorescence Methods, Visual Inspection and Photographic Visual Examination in Initial Caries Lesion: A Systematic Review and Meta-Analysis

2021 ◽  
Vol 9 (3) ◽  
pp. 30
Author(s):  
Mai Thi Giang Thanh ◽  
Ngo Van Toan ◽  
Do Thi Thanh Toan ◽  
Nguyen Phu Thang ◽  
Ngoc Quang Dong ◽  
...  
Keyword(s):  
Systematic Review ◽  
Quality Assessment ◽  
Visual Inspection ◽  
Early Stage ◽  
Meta Analysis ◽  
Diagnostic Value ◽  
Caries Detection ◽  
Permanent Teeth ◽  
Visual Examination ◽  
Initial Caries

This systematic review and meta-analysis aimed to investigate the efficacy of fluorescence-based methods, visual inspections, and photographic visual examinations in initial caries detection. A literature search was undertaken in the PubMed and Cochrane databases. Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines were followed, and eligible articles published from 1 January 2009 to 30 October 2019 were included if they met the following criteria: they (1) assessed the accuracy of methods of detecting initial tooth caries lesions on occlusal, proximal, or smooth surfaces in both primary and permanent teeth (in clinical); (2) used a reference standard; (3) reported data regarding the sample size, prevalence of initial tooth caries, and accuracy of the methods. Data collection and extraction, quality assessment, and data analysis were conducted according to Cochrane standards Quality Assessment of Diagnostic Accuracy Studies-2. Statistical analyses were performed using Review Manager 5.3 and STATA 14.0. A total of 12 eligible articles were included in the meta-analysis. The results showed that the sensitivity and specificity of fluorescence-based methods were 80% and 80%, respectively; visual inspection was measured at 80% and 75%, respectively; photographic visual examination was measured at 67% and 79%, respectively. We found that the visual method and the fluorescence method were reliable for laboratory use to detect early-stage caries with equivalent accuracy.

scholarly journals High performing flexible optoelectronic devices using thin films of topological insulator

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Animesh Pandey ◽  
Reena Yadav ◽  
Mandeep Kaur ◽  
Preetam Singh ◽  
Anurag Gupta ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Nonlinear Optical ◽  
Near Infrared ◽  
Optoelectronic Devices ◽  
Nonlinear Optical Properties ◽  
Metallic Surface ◽  
Strong Light ◽  
High Performing ◽  
Decay Times

AbstractTopological insulators (TIs) possess exciting nonlinear optical properties due to presence of metallic surface states with the Dirac fermions and are predicted as a promising material for broadspectral phodotection ranging from UV (ultraviolet) to deep IR (infrared) or terahertz range. The recent experimental reports demonstrating nonlinear optical properties are mostly carried out on non-flexible substrates and there is a huge demand for the fabrication of high performing flexible optoelectronic devices using new exotic materials due to their potential applications in wearable devices, communications, sensors, imaging etc. Here first time we integrate the thin films of TIs (Bi2Te3) with the flexible PET (polyethylene terephthalate) substrate and report the strong light absorption properties in these devices. Owing to small band gap material, evolving bulk and gapless surface state conduction, we observe high responsivity and detectivity at NIR (near infrared) wavelengths (39 A/W, 6.1 × 108 Jones for 1064 nm and 58 A/W, 6.1 × 108 Jones for 1550 nm). TIs based flexible devices show that photocurrent is linearly dependent on the incident laser power and applied bias voltage. Devices also show very fast response and decay times. Thus we believe that the superior optoelectronic properties reported here pave the way for making TIs based flexible optoelectronic devices.

scholarly journals Facile fabricating of rGO and Au/rGO nanocomposites using Brassica oleracea var. gongylodes biomass for non-invasive approach in cancer therapy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fatemeh Yousefimehr ◽  
Saeed Jafarirad ◽  
Roya Salehi ◽  
Mohammad Sadegh Zakerhamidi
Keyword(s):  
Breast Cancer ◽  
Green Synthesis ◽  
Cancer Cells ◽  
Brassica Oleracea ◽  
Photothermal Therapy ◽  
Breast Cancer Cells ◽  
Near Infrared ◽  
Therapeutic Effects ◽  
Invasive Approach ◽  
Au Nps

AbstractIn this study, we report a facile green-synthesis route for the fabrication of reduced graphene oxide (rGO) using biomass of Brassica oleracea var. gongylodes (B. oleracea). In addition, we have attempted to provide a green synthesis approach to prepare Gold nanoparticles (Au NPs) on the surface of rGO by using stem extract of B. oleracea. The synthesized Au/rGO nanocomposite was evaluated using UV–visible and FTIR spectroscopy, XRD, Raman, FE-SEM, EDX, AFM and DLS techniques. The obtained results demonstrated that the synthesized Au NPs on the surface of rGO was spherical with sizes ranging about 12–18 nm. The Au/rGO NC was, also, developed as photo-synthesizer system for the photothermal therapy (PTT) of MCF7 breast cancer cells. The near-infrared (NIR) photothermal properties of Au/rGO NCs was evaluated using a continuous laser at 808 nm with power densities of 1 W.cm−2. Their photothermal efficacy on MCF7 breast cancer cells after optimizing the proper concentration of the NCs were evaluated by MTT assay, Cell cycle and DAPI staining. In addition, the potential of the synthesized Au/rGO NCs on reactive oxygen species generating and antioxidant activity were assessed by DPPH. Au/rGO NCs possess high capacity to light-to-heat conversion for absorption in range NIR light, and it is able to therapeutic effects on MCF7 cells at a low concentration. The maximum amount of cell death is 40.12% which was observed in treatment groups that received a combination of Au/rGO NCs and laser irradiation. The results demonstrate that the nanomaterials synthesized by green approach lead to efficient destruction of cancer cell and might thus serve as an excellent theranostic agent in Photothermal therapy applications.

Structure and microstructure of near infrared-absorbing Au–Au2S nanoparticles

2007 ◽  
Vol 22 (9) ◽  
pp. 2531-2538 ◽  
Author(s):  
Mei Chee Tan ◽  
Jackie Y. Ying ◽  
Gan Moog Chow
Keyword(s):  
Optical Properties ◽  
Surface Segregation ◽  
Near Infrared ◽  
Small Degree ◽  
Core Shell ◽  
Shell Microstructure ◽  
Absorption Bands ◽  
Interfacial Effects ◽  
Nir Absorption ◽  
Structure And Microstructure

Near infrared (NIR) absorbing nanoparticles synthesized by the reduction of HAuCl4 with Na2S exhibited absorption bands at ∼530 nm, and in the NIR region of 650–1100 nm. The NIR optical properties were not found to be related to the earlier proposed Au2S–Au core-shell microstructure in previous studies. From a detailed study of the structure and microstructure of as-synthesized particles in this work, S-containing, Au-rich, multiply-twinned nanoparticles were found to exhibit NIR absorption. They consisted of amorphous AuxS (where x = 2), mostly well mixed within crystalline Au, with a small degree of surface segregation of S. Therefore, NIR absorption was likely due to interfacial effects on particle polarization from the introduction of AuxS into Au particles, and not the dielectric confinement of plasmons associated with a core-shell microstructure.

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