The aim of this study was to evaluate the level of aerosol pol lution following dental procedures performed in 15 sessions with an ultrasound scaler and a bicarbonate cleaner. The air contamination was measured by means of the Surface Air System method and the plate method (Air Microbial Index). Each colony-forming unitper cubic meter of air was allotted a unit value for statistical analysis. The data were then compared with the hygienic assessments made in previous studies. The results showed that the initial environmental conditions in a dental office initiated at the level of mediocre, then became very bad during dental procedures, and fell between mediocre and very bad at the end of the procedures.