Ultrasonic scalers are an essential and widely used instrument in the administration of dental hygiene care. Research shows that significant amounts of contaminated aerosols are generated during ultrasonic scaling, including blood and pathogenic bacteria. These contaminated aerosols remain suspended in the air for up to thirty minutes following ultrasonic procedures, and, therefore, could potentially be aspirated or contaminate a variety of surfaces (eg, computer keyboards, clothing, charts).1,3,4 Approved methods for reducing and virtually eliminating potentially harmful aerosols include the use of high-volume evacuators (HVEs) and antimicrobial preoperative mouthrinses. This article reviews and summarizes findings from the literature concerning aerosols produced during ultrasonic scaling and the methods for reducing or eliminating potential exposure to contaminated aerosols.
Dental hygienists are obligated to recognize potential health risks and identify the need for precautions to ensure dental hygiene care is delivered safely. The oral cavity contains billions of organisms (ie, bacteria, viruses, fungi) of hundreds of different species. The majority of bacteria residing in the oral cavity are benign and beneficial, such as certain strains of streptococci, lactobacilli, staphylococci, corynebacteria, and a high number of bacteroides.5 Practitioners must also be mindful of the specific pathogenic organisms that are responsible for the development of infections or disease, including those responsible for caries, periodontal disease, the common cold, pneumonia, tuberculosis, herpes, hepatitis B, and HIV/AIDS. The oral cavity is a unique environment that is conducive to the development of biofilm. As researchers learn more about the complexity of dental plaque bacteria and its interaction in the biofilm matrix, reducing and eliminating exposure to this bacteria for dental hygienists and patients should be considered.
Advanced Instrumentation for Hygiene
For over a half a century, magnetostrictive and piezoelectric ultrasonic units—which have similar actions and results—have been used in dentistry.6,7 There are many benefits associated with the use of ultrasonic instrumentation in periodontal therapy. First, little or no pressure is needed, which decreases operator fatigue, increases tactile sensitivity, and removes deposits in a more efficient manner. Cavitation and acoustic turbulence from the ultrasonic tip disrupt plaque biofilm, destroy subgingival pathogens, and flush debris (eg, bacteria, calculus, toxins,) out of the pocket area.8 Less tooth structure is removed and a smoother surface is achieved with ultrasonics, as compared to hand instrumentation.6,7 Though the ultrasonic vibration creates a high-pitched noise that could potentially be irritating to sensitive ears, patients often prefer the ultrasonic scaling technique over the “scraping” they experience with hand instrumentation. Ultrasonics are of further value to the hygienist’s armamentarium due to their ability to produce exceptional results with minimal tissue distention and improved deposit removal, resulting in decreased healing time and less trauma. All of these benefits are leading to widespread use of ultrasonics, and, therefore, the need for the dental hygienist to consider the potential risks.
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A 2005 survey of dental hygienists nationwide revealed that there are some significant misconceptions about the use of ultrasonic scalers.9 King and Muzzin discovered that, of the hygienists surveyed, 59% stated that they would not use the ultrasonic scaler when treating patients known to have a history of Hepatitis B, and 65% said that they would not use ultrasonics if the patient had a history of HIV/AIDS. They felt that HIV/AIDS and Hepatitis B could be transmitted through aerosol. Since many hygienists justified not using the ultrasonic scaler on patients that report HIV/AIDS or Hepatitis, what is the justification for using this instrument on the patient of unknown status? If practitioners are concerned about microbes spreading through aerosol, preventive practices should be consistent and standard precautions should be followed with all patients and procedures.
Research has shown that aerosols and bacteria can be significantly reduced with the use of an HVE and antimicrobial rinsing prior to dental or dental hygiene treatment.3,10-12 The American Dental Association and the Centers for Disease Control and Prevention, therefore, recommend routine use of HVEs and preoperative rinses for dental procedures.7 When adhered to, standard precautions protect both the practitioner and patient from microbial cross contamination. The evidence supporting the use of HVEs and antimicrobial rinses should be considered as standard precautions in infection control. With all that the dental hygienist must consider during an appointment, infection control should be habitual, thorough, meticulous, and practiced for every patient.
Practicing without the use of a dental assistant can create a dilemma in the already hectic day of the practitioner. High-volume evacuation tips reduce aerosol and water by attaching to the high-volume suction. Although some devices designed to slide over the cavitron handle increase the bulk of the instrument, they effectively reduce aerosol and fluid building. Even the use of the saliva ejector placed in the corner of the mouth while utilizing an ultrasonic scaler will reduce potentially harmful aerosol.
These recommendations must be accompanied by a preoperative rinse with an antimicrobial oral rinse in order to maximize the protection from potentially pathogenic aerosols. Chlorhexidine gluconate has been shown to create the greatest reduction in pathogenic aerosol.13 Cetylpyridinium chloride and essential oils may also be used to reduce microbial aerosol, though they may not be as significant as chlorhexidine.12 Most of these preoperative rinses are well received by most patients.
The use of an antimicrobial rinse should become part of every dental hygienist’s clinical practice. The addition of high-volume suction should become an integral part of every procedure that includes the use of an ultrasonic scaler. These simple additions to patient care will help to maintain good systemic health in the clinician, the dental staff, and the patient.
* Professor, University of the Pacific, Stockton, California.
†Clinical Affiliate Instructor, Idaho State University, Pocatello, Idaho.
- Harrel SK, Barnes JB, Rivera-Hidalgo F. Aerosol and splatter contamination from the operative site during ultrasonic scaling. J Am Dent Assoc 1998;129(9):1241-1249.
- Taggart JA, Palmer RM, Wilson RF. A clinical and microbiological comparison of the effects of water and 0.02% chlorhexidine as coolants during ultrasonic scaling and root planing. J Clin Periodontol 1990;17(1):32-37.
- Timmerman MF, Menso L, Steinfort J, et al. Atmospheric contamination during ultrasonic scaling. J Clin Periodontol 2004;31(6):458-462.
- Al Maghlouth A, Al Yousef Y, Al Bagieh N. Qualitative and quantitative analysis of bacterial aerosols. J Contemp Dent Pract 2004;5(4):91-100.
- Todar K. The bacterial flora of humans. 2007. Available at: http://www.textbookofbacteriology.net/normalflora.html. Accessed April 1, 2008.
- Bennett BL. Using power scaling to improve periodontal therapy outcomes. Contemp Oral Hyg 2007;7(6):14-21.
- Darby ML, Walsh MM (eds). Dental Hygiene Theory and Practice. 2nd Ed. St. Louis, MO: Saunders; 2003.
- Olsen I, Socransky SS. Ultrasonic dispersion of pure cultures of plaque bacteria and plaque. Scand J Dent Res 1981;89(4):307-312.
- King TB, Muzzin KB. A national survey of dental hygienists’ infection control attitudes and practices. J Dent Hyg 2005;79(2):8.
- Mohammed CI, Manhold JH, Manhold BS. Efficacy of preoperative oral rinsing to reduce air contamination during use of air turbine handpieces. J Am Dent Assoc 1964;69:715-718.
- Veksler AE, Kayrouz GA, Newman MG. Reduction of salivary bacteria by pre-procedural rinses with chlorhexidine 0.12%. J Periodontol 1991;62(11):649-651.
- Wyler D, Miller RL, Micik RE. Efficacy of self-administered preoperative oral hygiene procedures in reducing the concentration of bacteria in aerosols generated during dental procedures. J Dent Res 1971;50(2):509.
- Hererra D, Roldán S, Santacruz I, et al. Differences in antimicrobial activity of four commercial 0.12% chlorhexidine mouthrinse formulas: An in vitro contrast test and salivary bacterial counts study. J Clin Periodontol 2003;30:307-314.