Quantitative analysis of bacterial aerosols in two different dental clinic environments

Abstract

Microbial aerosols are generated during dental treatments and may represent an important source of infection. This study was designed to quantify bacterial air contamination during dental treatments in both a closed dental operatory and a multichair dental clinic. Air was sampled by using a slit type of biological air sampler. Following air sampling, blood-supplemented Trypticase soy agar plates were incubated at 37؇C under anaerobic conditions for 7 days. The maximum levels of air contamination in the closed dental operatory were observed while dental treatments were being performed (four trials; 216 ؎ 75 CFU/m 3 for ultrasonic scaling treatments and 75 ؎ 22 CFU/m 3 for operative treatments). At 2 h after completion of the treatments, the bacterial counts were about the same as the pretreatment levels (12 to 14 CFU/m 3). In the second part of the study, a multichair dental clinic was divided into four areas, and air contamination was monitored at each site. Three sites were located in active dental treatment areas, whereas no dental treatments were performed within an 11-m radius of the fourth site. At 3 h after the beginning of dental treatments, the highest bacterial counts were obtained in the three active dental treatment areas (76 to 114 CFU/m 3). However, there was noticeable contamination in the inactive dental treatment area (42 CFU/m 3). Thus, bacterial aerosols were able to spread into areas where there was no dental activity. My data show that dental treatments significantly increased the levels of bacterial air contamination in both a closed dental operatory and a multichair dental clinic. Whether such levels of contamination have any influence on infection rates is not known.

A pilot study of bioaerosol reduction using an air cleaning system during dental procedures

“…9 High-speed dental handpieces and ultrasonic scalers are known to produce airborne particles with microbial components originating from a number of sources within the mouth. 5 In addition to microorganisms from the patient, the water cooling system used in conjunction with these instruments can be a source of bioaerosol infection. One caveat when interpreting the fi ndings from the present study is therefore the possible infl uence of differing levels of microbial contamination within the DUWLs of the dental chairs used.…”

“…Finally, the potential risk that the bioaerosol presents to an individual will depend on their immune status. 5 It is not surprising that a range of approaches and practices have been developed in an effort to reduce the impact of bioaerosols in the dental setting. The use of high-volume wide-bore aspiration and pre-procedural antiseptic mouth rinse have both been demonstrated to reduce the risk of airborne spread of infection.…”

“…The use of a dental turbine handpiece, three-in-one syringe or ultrasonic scaling instrument has been reported to increase bioaerosol levels dramatically. 5,[9][10][11] The microbial component of these aerosols can originate from a variety of patient sources including plaque, calculus, dental materials, blood, saliva, nasopharynx 9 , and inadequately disinfected dental unit waterlines (DUWL). 12 The latter is increasingly recognized as a potential source of infectious agents whose growth within DUWLs in the form of recalcitrant biofi lms makes their removal problematic.…”

“…12 The latter is increasingly recognized as a potential source of infectious agents whose growth within DUWLs in the form of recalcitrant biofi lms makes their removal problematic. 13 While the development of bacterial air contamination during dental procedures is well recognized, 5,[9][10][11] limited information is available concerning the effectiveness of any dedicated air cleaning system (ACS), including the 1 Undergraduate dental student, 2 Reader in Oral Microbiology, 3 • Dental procedures create bioaerosols that are a potential vector for transmission of infection in the dental surgery.…”

Possible aerosol transmission of COVID-19 and special precautions in dentistry

“…When combined with bodily fluids in the oral cavity, such as blood and saliva, bioaerosols are created. These bioaerosols are commonly contaminated with bacteria, fungi, and viruses, and have the potential to float in the air for a considerable amount of time and be inhaled by the dentists or other patients (Grenier, 1995;Jones and Brosseau, 2015).…”