PREPROCEDURAL MOUTHRINSING REDUCES THE NUMBER OF
TRANSMISSIBLE MICROORGANISMS IN DENTAL AEROSOLS—
POSSIBLY DECREASING INFECTION RISK.
By Mary Jacks, RDH, MS
The oral cavity contains a host of transmissible
bacteria and viruses, including
bacterial strains Streptococcus, Actinomyces,
Lactobacillus, Staphylococcus, and Candida.
The hepatitis B, hepatitis C, and human
immunodeficiency viruses and tuberculosis can also be
found in the oral cavity, as well as in the nose, throat, and
respiratory tract. Secretions from the oronasal pharynx may
contain pathogenic microorganisms, such as cold,
influenza, or herpes viruses.1 These bacteria and viruses can
be transmitted via the dental aerosols produced during
ultrasonic instrumentation and polishing. Aerosols are characterized
as the cloud of mist emanating from ultrasonic
scalers and air abrasive polishing devices. The aerosol particles
are as small as 10 μ, (equal to 0.01 mm) and have
the potential to penetrate and lodge in the narrow passages
of the lungs.1
Although the United States Centers for Disease Control
and Prevention considers the risk of infection from airborne
pathogens "minimal" for oral health professionals, clinicians
must adhere to stringent infection control protocols.2 The
use of preprocedural mouthrinses prior to delivering care
may reduce the risk of infection for both clinicians and
The use of antimicrobial mouthrinses by patients before the
provision of dental care is designed to decrease the number
of microorganisms emitted within the dental aerosols
produced during power instrumentation and polishing. These aerosols
and spatter are potential sources of contamination.2
Any antimicrobial mouthrinse may be used during preprocedural
rinsing. Research has demonstrated the efficacy of chlorhexidine gluconate
(CHX) mouthrinse, which is available by prescription only.3
Over-the-counter rinses containing antimicrobials, such as essential
oils4 and cetylpyridinium chloride (CPC),5 are also effective, and can
be found in almost every operatory. The antimicrobial rinse must be
swished around the oral cavity for at least 30 seconds immediately
prior to beginning treatment in order to be effective.
Since the 1990s, studies on the benefits of preprocedural
mouthrinses that contain CHX6 and essential oils7 have been compared
to the effects of rinsing with water alone. These studies found that
CHX and essential oil mouthrinses were more effective than water
in reducing bacterial loads, while rinsing with water reduced the
load better than not rinsing at all.6,7
Although the evidence does not demonstrate that preprocedural
mouthrinsing prevents infection in patients or clinicians, studies do
show that rinsing with an antimicrobial mouthrinse reduces the
number of bacteria generated during dental procedures.7–9 The typical
study design compared the number of bacterial colony-forming
units by placing collection plates or filters in various areas of the
dental operatory. This study design is most effective when collecting
spatter-sized particles—large particles visible with the naked
eye that travel quickly from the point of origin to the place of rest.
The results of studies utilizing this collection technique vary, though
all share three common themes: rinsing with an antimicrobial
mouthrinse reduced particles more than rinsing with water; rinsing
for a period of 30 seconds to 60 seconds was as effective as rinsing
for 120 seconds; and rinsing with water reduced more particles
than no prerinse prior to treatment.6,7,9
To determine if one active ingredient was most effective in
reducing aerosolized particles, Feres et al compared preprocedural
mouthrinses among four patient groups, including: rinsing with
CPC; rinsing with CHX; rinsing with water; and no rinsing.5 The
results indicated that CPC and CHX equally reduced bacteria from
the spatter-sized particles, while water reduced bacteria presence
more than no prerinse.5 A similar study design determined the
effectiveness of preprocedural rinsing on aerosol contamination
during ultrasonic instrumentation. This study compared CHX with
an herbal mouthrinse and water. The results of this study found the
CHX prerinse was most effective, and the herbal mouthrinse
reduced more particles than water prerinse.10 Other studies yielded
similar results, demonstrating that prerinsing with an antimicrobial
rinse was more effective than prerinsing with water.1,7 Temperature
control for CHX was evaluated by Reddy et al,11 who found that
warming the rinse to 140° increased its antimicrobial effect. These
studies looked at the effect of preprocedural mouthrinse against
free-floating bacteria in the oral cavity. A potentially greater risk,
however, comes from subgingival biofilm, which is protected from
the rinsing action.
Current disease transmission theories teach a three-stage cycle to
spread infection: an infection source; a mode of transmitting the
infection; and a susceptible host. To block the spread of infection, a
break in this cycle must occur. Unfortunately, no single method of
protection is foolproof, and the true nature of potential threats—with
new viruses discovered often—remains unknown.
Incorporating the use of preprocedural mouthrinsing before treatment
is one facet of the layered approach to preventing infection via
dental aerosols, which includes the use of personal protective equipment
and high volume evacuation. In addition, careful consideration
should be given to the amount of bacterial biofilm present during
ultrasonic instrumentation. Future study is needed on the effects of
basic plaque removal (brushing, flossing, or polishing) prior to ultrasonic
- Harrel SK, Molinari J. Aerosol and splatter in dentistry: a brief review
of the literature and infection control implications. J Am Dent Assoc.
- Cole EC, Cook CE. Characterization of infectious aerosols in health care
facilities: an aid to effective engineering controls and preventive strategies.
Am J Infect Control. 1998;26:453–464.
- Moshrefi A. Chlorhexidine. J West Soc Periodontol Periodontal Abstr.
- Baqui AA, Kelley JI, Jabra-Rizk MA, Depaola LG, Falkler WA, Meiller TF. In
vitro effect of oral antiseptics on human immunodeficiency virus-1 and
herpes simplex virus type 1. J Clin Periodontol. 2001;28:610–616.
- Feres M, Figueiredo LC, Faveri M, Stewart B, de Vizio W. The effectiveness
of preprocedural mouthrinse containing cetylpyridinium chloride in
reducing bacteria in the dental office. J Am Dent Assoc. 2010;141:415–422.
- Logothetis DD, Martinez-Welles JM. Reducing bacterial aerosol
contamination with a chlorhexidine gluconate pre-rinse. J Am Dent Assoc.
- Fine DH, Mendieta C, Barnett ML, et al. Efficacy of preprocedural
rinsing with an antiseptic in reducing viable bacteria in dental
aerosols. J Periodontol. 1992;63:821–824.
- Centers for Disease Control and Prevention. Infection Control, Frequently
Asked Questions, Preprocedural Mouth Rinse. Available at: www.cdc.gov/
October 18, 2013.
- DePaola LG, Minah GE, Overholser CD, et al. Effect of an antiseptic
mouthrinse on salivary microbiota. Am J Dent. 1996;9:93–95.
- Gupta DG, Mitra DD, K P DA, et al. Comparison of efficacy of preprocedural
mouth rinsing in reducing aerosol contamination produced by
ultrasonic scaler: a pilot study. J Periodontol. 2013:1–12.
- Reddy S, Prasad MG, Kaul S, Satish K, Kakarala S, Bhowmik N. Efficacy
of 0.2% tempered chlorhexidine as a pre-procedural mouth rinse: A clinical
study. J Indian Soc Periodontol. 2012;16:213–217.
From Dimensions of Dental Hygiene. November 2013;11(11):46,48.