|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,700,000 (Direct Cost : ¥1,700,000)
Air of the dental operating room is contaminated with airborne particles, produced during the dental operation, such as dentine tip, saliva, blood, bacteria and virus.
Suction and removal of these particles through the extra-oral or intra-oral aspirator is a crusial procedure to prepare sound and comfortable environment of patients and dental staffs.
Various kinds of dental aspirators have appeared on our market, but little is known about the characteristics of the aspirators. At the moment each producer introduced its own standard.
The results were as follows.
1. Electrical and mechanical properties
Wind velocity of the extra-oral vacuum aspirator (EOVA) was 3.2-3.70 m^3/min. This velocity corresponded to 10200 times that of the ejector, and was 22 times that of the intra-oral vacuum aspirator (IOVA).
Suction noise of the EOVA was measured using a noise meter.
Among the aspirators examined the conventional type showed large difference between A mode and C mode, Namely this means the noise of
a conventional aspirator distributed in the low frequency range. On the whole, most of the new type aspirators showed no difference in these values.
Peak current at the closure of the EOVA was 7.1-19.7 A in the new types, and was 1.4-2.0 times current at the stable phase, though peak current was 30-37 A in the conventional type.
2. The total evaluation of the aspirator in the clinical practice
The effect of the aspirator was examined. The number of particles per a definite volume of air was adopted as the marker of the particles produced during the tooth preparation. As the result, there were 7.7 times increase in the '0.3mum particle', 53 times increase in the '0.5mum particle', 151 times increase in the '1mum particle', 127 times increase in the '2mum particle', 28 times increase in the '5mum particle', respectively, as compared with the number of particles before the preparation.
In the case of using both of EOVA and IONA,particles more than 0.5mum' has decreased to the level of the number of the particle before the preparation. The EOVA showed higher effectiveness on sucking '5mum particle' than the IOVA. Less