Study of the measurement of halitosis by thin film semi-conductor sensor

Research Project

Project/Area Number	63870083
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	小児・社会系歯学
Research Institution	TOHOKU UNIVERSITY
Principal Investigator	SHIMADA Yoshihiro Tohoku University Dentistry Professor, 歯学部, 教授 (40005012)
Co-Investigator(Kenkyū-buntansha)	SAKAI Sai New Cosmos Electric Co., Ltd. Cosmos Research Laboratory Chief Researcher, コスモス研究所, 主任研究員 YASUNO Yoko Tohoku University Dentistry Coadjutor, 歯学部, 助手 (90177296) IWAKURA Masaki Tohoku University Dentistry Assistant Professor, 歯学部, 助教授 (90005067)
Project Period (FY)	1988 – 1989
Project Status	Completed (Fiscal Year 1989)
Budget Amount *help	¥11,700,000 (Direct Cost: ¥11,700,000) Fiscal Year 1989: ¥4,900,000 (Direct Cost: ¥4,900,000) Fiscal Year 1988: ¥6,800,000 (Direct Cost: ¥6,800,000)
Keywords	Halitosis / Volatile Sulfur Compound / Thin Film Sensor / Measurement / Mouth Air Chamber / 半導体薄膜センサ / 口臭測定器
Research Abstract	The present time, in general dental clinic, the judgment of halitosis of the patients who complaining bad breath is due to the olfactory sense of dentists. But the olfactory sense of panelists is changed by their physical condition or aging. For avoiding these troubles, the panelists must be tested of their olfactory sense by standard method and plural panelists are needed. Because of these many limitations, reliable analytical method was expected. We reported that the concentration of volatile sulfur compounds(VSC) analyzed by gas chromatography is well correspond to the judgement of halitosis by panel. But in general dental clinic, it is very hard to prepare the gas chromatography, for needed special techniques and high cost. So, the development of convenient olfactometer was expected. We aimed to develop a convenient olfactometer composed of thin film zinc oxide semi-conductor sensor which is high selective to VSC. We made the first and the second trial olfactometer and tested their e … More fficiency. The result are as follows. The sensitivity of this sensor is sufficient to detect noticeable halitosis revel of VSC. The sensitivity revel of acetone and ethylalcohol, the typical organic contents in mouth air, are 1/10 fold lower than VSC which shows good selectivity of this sensor. Repeating measuring test to standard halitosis air is sufficient reproducibility. The selectivity is improved by using acidic absorbent filter. A mouth air chamber which accumulate a certain volume of mouth air, is useful to decreasing the detective variance and is also useful to protect the contamination of saliva into the detective path. The practice measuring was done to mouths, using this olfactometer, and the time for preheat is about 3 minutes, measuring time is one and half minutes and about 3 minutes is necessary for the next measuring. But repeating measurements to same person with passage time showed considerable variance. Further study is necessary whether this variance was caused by the changes of mouth odor with passage of time or whether by the sampling methods of mouth air. Less