An examination of the air pollution in a dental hospital, with special reference to air-borne bacteria.

Abstract

The environmental problems in dental clinics claim our attention because of the special nature of dental treatment such as cutting and grinding of the teeth and prosthetic material. In recent years, the air turbine engine developed as a super high speed apparatus for the cutting of teeth has come to be widely used in dental treatment. But because the cutting of teeth has become highly effective, dental cuttings, saliva and bacteria from the mouth of patients cause pollution of the air inside dental clinics.The present study was made of the air-borne bacteria in various clinics at dental hospital N. Pure cultures were made of the bacteria and their bacteriological characteristics were investigated. The following conclusions were obtained.1. Bacterial counts in the clinics were 0.41-2.13/l in April, 0.41-1.41/l in July and 0.30-2.27/l in December. The bacterial count in clinic A for five days was 0.26-1.12/l. The number of air-borne bacteria during dental treatment was to 3.1 to 7.6 times more than during the pre-treatment stage.2. The correlation between the number of patients and bacterial counts in the various clinics was 0.406-0.777. The correlation for five days in clinic A was 0.971. Thus a high correlation was observed between the density of patients and bacterial counts.3. Bacteriological characteristics.1) The air-borne becteria at dental hospital N consisted of 12.4% Myces, 34% bacilli, and 53.6% cocci.2) From the pure cultures of air-borne bacteria, we found that gram-positive cocci were 117 (51.5%), gram-negative cocci were 22 (9.7%), gram-positive bacilli were 71 (31.3%), and gram-negative bacilli were 17 (7.5%).3) Those which proved to be positive in hemolytic reaction either to human or horse blood were 70 (30.8%). Of them, a hemolytic types were 12 and 9 hemolytic types were 55, and 3 proved to be a hemolytic to human blood and β hemolytic to horse blood.4) 5 Gram-positive bacilli were proved to from spores, accounting for 7.0%.5) Among the air-borne bacteria in the clinics, the existence of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Micrococcus, Bacillus subtilis and Serratiawas confirmed.