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Aerosols and splatter in dentistry
COMPOSITION OF DENTAL AEROSOLS
Qualitative and quantitative analysis of the makeup of dental aerosols would be extremely difficult, and the composition of aerosols probably varies with each patient and operative site. However, it is reasonable to suppose that components of saliva, nasopharyngeal secretions, plaque, blood, tooth components and any material used in the dental procedure, such as abrasives for air polishing and air abrasion, all are present in dental aerosols. In the past, studies usually concentrated on the number of bacteria present in dental aerosols; several recent studies have analyzed the presence of blood components in dental aerosols.21, 22
Multiple studies have been conducted to determine which dental procedure produces the most airborne bacterial contamination.23, 24, 25, 26, 27, 28 In these studies, researchers have measured the number of bacteria that settle on growth media plates over a specific period. In almost all instances, a nonselective bacterial growth media such as blood agar has been used. When an aerobic bacterium settles on the plates and grows as a colony, it will be counted as a colony-forming unit, or CFU. Most results have been reported as the total CFUs produced during the various dental procedures. This method gives a good picture of the increase in total airborne bacterial CFUs from a particular procedure, but it does not provide any differentiation between whether the bacteria are relatively benign or a pathogenic species. Any bacteria that require special media or growth conditions, such as mycobacteria or strict anaerobes that are common in periodontal pockets, will not grow on media used in these tests and therefore are not counted. Also, because they do not grow on the type of media used for bacterial studies, no viral particles such as influenza, rhinoviruses and SARS coronovirus would be measured. Table 2lists the dental instruments and procedures that produce the greatest amount of aerosols.
|Ultrasonic and Sonic Scalers||Considered the greatest source of aerosol contamination; use of a high-volume evacuator will reduce the airborne contamination by more than 95 percent|
|Air Polishing||Bacterial counts indicate that airborne contamination is nearly equal to that of ultrasonic scalers; available suction devices will reduce airborne contamination by more than 95 percent|
|Air-Water Syringe||Bacterial counts indicate that airborne contamination is nearly equal to that of ultrasonic scalers; high-volume evacuator will reduce airborne bacteria by nearly 99 percent|
|Tooth Preparation With Air Turbine Handpiece||Minimal airborne contamination if a rubber dam is used|
|Tooth Preparation With Air Abrasion||Bacterial contamination is unknown; extensive contamination with abrasive particles has been shown|
Because of the methods used, bacterial growth studies give only a partial picture of the airborne contamination that occurs during dental procedures. However, in relative terms these studies can be viewed as providing a good comparative index of the amount of airborne material that is generated during various dental procedures. Using the bacterial growth method, the ultrasonic scaler has been shown to produce the greatest amount of airborne contamination, followed by the air-driven high-speed handpiece, the air polisher and various other instruments such as the air-water syringe and prophylaxis angles.12, 23, 24, 25, 26, 27, 28 To date, no studies have been performed on the bacterial contamination produced by air abrasion.
Investigations have evaluated the presence or absence of blood contamination in the aerosols produced during root planing when an ultrasonic scaler is used.21, 22 These studies have shown that blood is present universally in ultrasonic scaler aerosols during root planing. While the presence of blood has not been directly studied, it would seem logical that blood also would be present in any dental aerosol that is produced by an instrument in a blood-contaminated field. This would include restorative procedures that extend subgingivally, as well as periodontal and oral surgery procedures.
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Harrel, S. K., & Molinari, J. (2004). Aerosols and splatter in dentistry: a brief review of the literature and infection control implications. Journal of the American Dental Association (1939), 135(4), 429–437. https://doi.org/10.14219/jada.archive.2004.0207