|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1995 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1994 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Dust in each grain size and airborne bacteria in dental hospitals were estimated to identify the distribution of dust and a relationship between the distribution of dust in each grain size and airborne bacteria or chronological factors were studied.
Methods : For two years from April in 1994, four days every month and three times a day, measurments were carried out in middle size-clinics (pedodontics and orthodontics) and large size-clinics (restoration and prosthetics) in dental hospital about dust in each grain size, airborne bacteria with an SY type pin hole sampler method and Koch's dropping method, and environmental factor (temperature, humidity, air flow, and number of persons, opened windows and outlets of functional air-conditioner). Correlation between dust and each measured factor was analyzed.
Results and Discussion : 1.Monthly averege of the distribution of dust in each grain size were 99,462-292,484/l at 0.3-0.5 mum, 14,401-73,510/l at 0.5-1.0 mum, 592-3,493/l at 1-2 mum, 108-588/l at 2-5 mum, 32-142/l at above 5 mum. The volume of dust presented high in spring and autumn, and low in summer and winter. 2.The bacterial count was 0.07-0.42CFU/l with the SY method and 0.69-3.14CFU with Koch's method. An increase and decrease of airborne bacterial count and dust volume showed to have a similar tendency.
Especially the dust volume at 1-2 mum with SY method and above 5mum with Koch's method indicated a high corelationship to airborne bacterial count. 3.Monthly averege of environmental factors were 20.9-27.4ﾟC,31.1-55.3% of humidity, 0.13-0.33m/sec of air flow, 8.5-46.5persons, 0.0-6.3 of windows and 0.0-15.0 of outlets. The functional air-conditioner gave a largest effect to dust volume compared with other factors.
As a result, we suggest that operating the air-conditioner in all seasons in neccesary in order to obtain amenable conditions in dental clinic.