It's a well-known fact that water-air aerosol can be a result of some dentist's activity during regular dental surgery and can contain broad range of microorganisms from dental plaque, saliva and pus. Assessment of dentist's activity impact on bacteria concentration in air of dentist surgery was a main purpose of this assay. Presented data contains results of four total number of bacteria and fungi in air assays made with fifty minutes intervals. Air samples was taken in dentist's office during regular dental surgery of patients afflicted with oral cavity infection with pus. Due to defective ventilation system, bacteria's concentration in air samples increased from less than thousand cfu/m3 to almost three thousands cfu/m3. Obtained results demonstrated that aerosol containing bacteria is released during regular dental surgery so the concentration of potentially infectious bacteria around patient and dentist can increase up to three thousands cfu/m3.