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Tests on Naturally Voided Body Fluids
Published in Robert B. Northrop, Non-Invasive Instrumentation and Measurement in Medical Diagnosis, 2017
From its origin in the lungs, exhaled breath should ideally contain only water vapor, CO2, O2, N2, and traces of CO, H2, and Ar. Unfortunately, one's breath is not always odorless. Halitosis is a term applied to the general phenomenon of unpleasant, malodorous, or bad breath. The offensive odors can be from several sources and in some cases can be of diagnostic value to a physician or dentist.
Advanced materials and technologies for oral diseases
Published in Science and Technology of Advanced Materials, 2023
Hao Cui, Yan You, Guo-Wang Cheng, Zhou Lan, Ke-Long Zou, Qiu-Ying Mai, Yan-Hua Han, Hao Chen, Yu-Yue Zhao, Guang-Tao Yu
The essence of halitosis is the release of sulfide gases by microorganisms in the oral cavity. By analyzing these sulfides, different markers can be found to diagnose different diseases [274]. One of the markers of halitosis, H2S, can be analyzed for effective monitoring of early oral diseases such as caries or periodontitis. Thanks to the advent of nanotechnology, such technology makes detection methods for oral gases more convenient and improves the sensitivity and specificity of detection [275,276]. Ba0.5Sr0.5TiO3 (BST) films have been prepared, and the voltage induced by the gas in the presence of electrical changes can instantly display the results of the detection of the gas [277]. However, this method also has some limitations. For example, it does not effectively display the actual concentration of hydrogen sulfide in the gas. Another detection idea is to add a dye indicator to the sensor made through nanotechnology. When the oral gas is collected, the concentration of hydrogen sulfide can be effectively calculated by using gas chromatography analysis [278,279]. Li et al. developed a wearable fluorescent mouthguard composed of zinc oxide-polydimethylsiloxane (ZnO-PDMS) nanocomposites, which can pinpoint the site of tooth damage by detecting the local release of VSCs (Figure 11) [25]. Compared with the previous method, this method is also more intuitive. Supposing this nanosensor is applied to the mouthpiece, it can enable people to instantly know their oral condition to perform early intervention that can effectively prevent oral diseases.