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Remaining Vigilant

With the growing risk of exposure to emerging and re-emerging diseases, the dental practice must maintain strict infection control protocols, including protection against airborne transmission.

Over the past several years, newly emerging diseases have been frequently reported. Some of the most recent are Marburg virus, Severe Acute Respiratory Syndrome (SARS), Ebola, West Nile fever, and bird or avian influenza. At the same time, reported outbreaks of diseases that were once considered controlled or eliminated are increasing, such as tuberculosis, Pertussis (whooping cough), and drug resistant Staphylococcus (MRSA). One of these emerging or reemerging diseases may be carried by patients seeking routine dental treatment and thus become a diagnostic and infection control concern for dental personnel.

Emerging Diseases

The most important and prevalent disease to emerge in the recent past is HIV/AIDS. A previously unknown disease, HIV/AIDS dramatically affected dental treatment and completely redefined dental infection control. HIV may have been present in Africa for many years but was not recognized as a defined disease entity until the early 1980s.1 Interestingly, one of the first hints of this new disease entity came from the observation of an increased incidence of Kaposi’s sarcoma, a lesion that is most often found in the oral cavity.2 Following the initial recognition of HIV, the disease was documented to spread from a relatively small population to the millions of cases that are now reported. Currently, the disease is frequently encountered during routine dental treatments. The effect of HIV on infection control in the dental office has led to the universal use of gloves, masks, and handpiece sterilization. Today it is difficult to envision performing hygiene procedures without these precautions, but less than 20 years ago these standard infection control procedures were almost never followed. In a brief period of time, HIV has overhauled the way dentistry is performed.

Table 1. Some Emerging Diseases
SARS Airborne and droplets. Aerosols must be controlled for all procedures.
Ebola and Marburg Virus Unknown, all body fluids including saliva, carry a risk of spreading infection. To date, outbreaks are very localized. Isolation is the only sure control.
West Nile Fever Mosquito bite, possibly blood products. May be a concern if bloodborne pathway is confirmed.
Emerging influenzas such as bird flu Droplets, aerosols, direct contact with patient. Aerosols must be controlled for all procedures.
Hepatitis C through E Body fluids and products, primarily blood and feces. Standard (universal) precautions.

It is unlikely another disease will emerge in the foreseeable future that will affect dental procedures to the same extent as HIV. First, many of the precautions and procedures that are now considered universal for dental treatment also protect against many newly emerging diseases. The exceptions are diseases that are routinely spread by an airborne route. The most documented of the emerging diseases spread in this manner is SARS but some of the newer flu-like diseases arising in parts of Asia may also be spread the same way as SARS./p>
During the initial outbreak, some investigators suspected that SARS was spread by aerosols and contaminated droplets but there was a general resistance to the possibility that it was a true airborne disease. Subsequent to the initial outbreak of SARS, detailed epidemiological analysis of the disease spread has given strong support for the airborne route of transmission. One of the largest clusters of SARS occurred at the Amoy Garden apartments in Hong Kong. Analysis of the disease spread-from the initial case within the apartment complex to the several hundred residents that eventually contracted the disease-clearly showed that the disease was spread via air currents from a vent pipe.3,4 Another study showed that a large number of SARS viral particles are present in the saliva, sputum, and tears of SARS patients. The authors of this study felt that the SARS virus may be universally present in the aerosols arising from SARS patients’ mouths. They also stated that these aerosols were the likely method for transmission of SARS from infected patients to health care workers who were not in direct contact with the patient.5

Many of the recommendations to control contaminated aerosols in medical care facilities and hospitals require major engineering changes, such as placing ultraviolet chambers in the ventilation system. Some of these changes are cost prohibitive for the average dental office. However, several relatively simple and inexpensive procedures can effectively limit the amount of contamination from dental procedures,7 such as the routine combined use of preprocedural rinses and large diameter high volume evacuators (HVEs) during all dental procedures. Because a preprocedural rinse only kills those organisms present in easily accessible areas, the use of a preprocedural rinse alone is inadequate. The most important step for control of airborne contamination is routine use of the HVE. A saliva ejector, because of its typical placement in the floor of the mouth and the small diameter of the tube, does not function as an HVE and is inadequate for the control of contaminated aerosols.7


Table 2. Some Reemerging Diseases
Tuberculosis Infected sputum, droplets, aerosols, droplet nuclei. Active TB patients should be treated in special clinics.
Measles, Pertussis Rubella Body secretions, droplets from coughing. Avoid treatment of active patients, control aerosols where suspected.
Methicillin Resistant Staphylococcus or MRSA Direct contact with the infected lesion or drainage. Maintain good barrier control without a break in technique.
Sexually Transmitted Diseases Direct contact with lesion, possibly in secretions. Avoid treatment of active patients, learn to recognize oral lesions.

Most emerging diseases initially present as flu-like symptoms characterized by fever, respiratory problems, and a feeling of malaise. In the case of SARS and avian flu, these symptoms may progress to respiratory distress and often death. Ebola and Marburg virus infections start in a similar flu-like manner and progress to generalized spontaneous bleeding and death. Marburg and Ebola are classified as hemorrhagic fevers because of the associated often fatal bleeding.8 It is unlikely that patients in the acute phases of these diseases would seek dental treatment but it is possible that dental treatment would be performed during the early flu-like phase. For this reason, patients who indicate they are “coming down with the flu” should have their appointment rescheduled so their treatment is performed after their symptoms have disappeared.

It is difficult to list the signs and symptoms of emerging diseases due to the fact that the diseases are often poorly understood. The lack of understanding of the diseases and the disease process are the main reasons that it should be assumed that all patients carry an infectious disease, hence the need for standard or universal precautions for all patients. Table 1 lists some of the emerging diseases, their method of transmission, and their relative risk to dentistry.

Reemerging Diseases

Many diseases once thought to be controlled or eliminated are returning to the general population and are increasingly likely to be seen in the dental office. The relaxing of vaccination schedules and requirements for children has led to the reemergence of many common childhood diseases as has the overuse or improper use of antibiotics. Many diseases that were easily treated with antibiotics 20 years ago are now resistant to most antibiotics. Some of the pathologic streptococci and staphylococci found in the oral cavity and nasal pharynx are now resistant to common antibiotics. The reemergence of tuberculosis in a drug resistant form is associated with the improper use of medication. If the anti-tuberculosis medications are not taken regularly and for the prescribed period of time, the disease reappears and the bacteria become resistant to standard drugs. A third reason is the increased number of immune compromised individuals.9 Many medications and diseases affect the body’s immune system, making a patient more likely to be infected by a disease that is easily controlled in a patient with a healthy immune system.

Gloves—Your First Line of Defense
Donning gloves is standard in infection control protocol within the dental setting. Gloved practitioners are the norm today but as recent as 20 years ago, many dental hygienists practiced without the protection of gloves. Fortunately, this is no longer the case as gloves can now be used to prevent to cross-contamination for both patient and clinician. With the growth of glove use, the incidence of chronic skin disease due to improper hand washing, exposure to chemicals, and possible allergic reactions has also increased. In order to better serve dental hygienists and other health care providers, glove manufacturers offer a variety of glove materials and coatings. Function, fit, feel, and comfort must all be considered when choosing gloves. Following are some of the materials and coatings currently available:

MATERIALSLatex. Derived from the Hevea tree, latex is the most common material used today due to its ability in barrier protection, fit, feel, comfort, tactile sensitivity, and high resistance to puncture and tear. The proteins in latex may cause allergic reactions and occupational asthma as may the chemicals, ie, accelerants, used in the treatment of latex. Low protein latex gloves are now available for nonlatex allergic oral health care personnel.Nitrile. A synthetic alternative to latex, nitrile is a polymer that does not contain any plant proteins, thereby reducing the possibility of allergic reaction. Although it has good puncture resistance, it tears easily once breached.

Polychloroprene. Mostly used for surgical gloves, it is sometimes used to make examination gloves. Chloroprene is similar to latex in comfort, fit, and feel but is more resistant to alcohols. However, once breached, polychloroprene tears easily and it is more expensive than latex.

Polyurethane. A newer material to the glove market, polyurethane contains no plant proteins and is similar in comfort, tactile sensitivity, and durability to latex. Polyurethane gloves are susceptible to breakdown with alcohol and are more expensive than latex. Vinyl. Another synthetic alternative to latex, vinyl is an effective barrier method but may wear out so gloves may need to be changed during an appointment. The chemicals used during vinyl’s treatment may still cause skin reactions.


Aloe-coated. Gloves are coated on the inside with aloe vera gel. The purpose of the gel is to moisturize the skin using the body’s heat to activate the gel for deep penetration.

Chlorinated coating. Used to make donning easier, chlorinated gloves have a lower residual protein content reducing the risk of allergic reaction. However, the chlorine exposure reduces their longevity.

Lightly powdered or powdered. To make gloves easier to don, cornstarch is added to the interior of the glove. Excessive cornstarch powder can be irritating to the skin and, when airborne, may also initiate allergies and occupational asthma. Advancement in glove manufacturing has created lightly powdered low protein gloves with greatly reduced irritation and allergenic potential.

Powder-free. Gloves made specifically without cornstarch powder to decrease the possibility of irritation.

Dimensions of Dental Hygiene/p>

Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus or MSRA is a disease likely to be encountered in a dental setting.10 This staphylococcal infection is an example of a bacterium that no longer responds to routine antibiotic treatment.

Staphylococcal infections of the skin and mucosa are some of the most common types of infections. In most cases, a mild infection is self-limiting and the body is able to control the infection without treatment. In the past, staphylococcal infections that were not self-limiting were relatively easily treated by antibiotics.

Many years ago, some staphylococcal infections were becoming increasingly resistant to routinely used antibiotics. These infections were usually associated with hospitals and became known as hospital resistant staphylococcus. Over time, these bacteria became resistant to stronger and stronger antibiotics until the only antibiotic that would control the infection was Methicillin. Recently some staphylococci have become resistant even to Methicillin. These were first noted in prisons and other institutional settings but within the past year, MRSA infections have been reported with increasing frequency in the general public.

The most likely situation where MRSA would be encountered in dentistry is as skin lesions on the patient’s face and lips. Staphylococcal infections are usually manifested by redness of the affected tissue as well as the classic signs of fever, pain, and malaise. These infections are spread relatively easily to other parts of the body, possibly including the oral mucosa. The greatest danger to the hygienist is from a break in standard barrier precautions. A likely scenario is for the hygienist’s gloved hand to come in contact with a patient’s skin lesion and then, by touch, transfer the bacteria to an unprotected part of the hygienist’s body. Any contact of the bacteria with micro-breaks in the skin or to eye and nasal mucosa is an opportunity for an infection.

As with emerging infections, defining specific signs and symptoms for diagnosing reemerging diseases is difficult. The presenting symptoms for many of the reemerging diseases can be described as flu-like. In the case of MRSA, the symptoms are boils or skin eruptions with possible red lesions in the mouth. Many of the oral manifestations of sexually transmitted diseases such as syphilis and gonorrhea are also first seen as red patches or boil-like lesions of the skin or mucosa. Only in later stages do diseases like Syphilis develop their classic signs of chancre or mucous patches on the tongue or palate. Table 2 lists some of the re-emerging diseases.

Infection Control Measures

Careful and strict adherence to standard infection control procedures offers protection from most of the diseases discussed. Because many of the emerging and reemerging diseases can be spread by droplets and aerosols, control of airborne contamination from operations such as ultrasonic scaling and air polishing need to be controlled with an HVE. The CDC has recommended the use of an HVE whenever droplet or aerosols are produced during dental procedures11 but this recommendation is often ignored during the performance of hygiene procedures. This is an unacceptable risk.

Treatment of patients with flu-like symptoms should be avoided. Not treating patients with a fever of unknown origin or those with signs of respiratory symptoms was a major factor in the control of the SARS outbreak in Asia. In areas where SARS cases were known to exist, signs were placed in waiting rooms indicating that treatment would not be performed if the patient had a fever or flu-like symptoms. It was recommended that treatment be postponed until at least 24 hours after the flu symptoms or fever had disappeared. In the dental office, where adhering to a schedule and seeing a certain number of patients in a day are major goals, there may be a tendency to see patients even if they are a little sick. The inherent danger of this practice should be discussed with all staff members who are responsible for scheduling patients and an office policy should be in place to help protect the entire dental staff.

Hygienists need to be constantly aware of the rapidly changing landscape of infectious diseases. The very nature of an emerging disease makes it impossible to predict what, if any, special infection control procedures may be necessary to control the spread of the disease. The current standard infection control procedures recommended for dentistry, if followed closely and routinely, are adequate to protect the hygienist and other patients from the transmission of most diseases. The infection control lapses encountered in dental treatment facilities are often due to the fact that our infection control procedures are performed multiple times during the day. As with all routine procedures, it is easy to become careless performing the basic steps of infection control. This often occurs as we become tired or rushed in trying to stay on schedule. The hygienist should be constantly vigilant in maintaining strict infection control standards.


  1. Lange M, Buimovici-Klein E, Kornfeld H, et al. Prospective observations of viral and immunologic abnormalities in homosexual males. Ann N Y Acad Sci. 1984;437:350-363./li>
  2. Gottlieb GJ, Ragaz A, Vogel JV, et al. A preliminary communication on extensively disseminated Kaposi’s sarcoma in young homosexual men. Am J Dermatopathol. 1981;3:111-1114.
  3. Hong Kong government news service. Amoy Gardens investigation findings made public. Available at: Accessed June 19, 2004.
  4. Yu IT, Li Y, Wong TW, et al. Evidence of airborne transmission of the severe acute respiratory syndrome virus. New Eng J Med. 2004;350:1731-1739.
  5. Wang W-K, Chen S-Y, Liu I-J, et al. Detection of SARS-associated coronavirus in throat wash and saliva in early diagnosis. Emerg Infect Dis. Available at: Accessed August 22, 2004.
  6. Airborne transmission underestimated as cause when investigating disease outbreaks. Harvard school of public health news release. Available at: Accessed June 19, 2004.
  7. Harrel SK, Molinari J. Aerosols and splatter in dentistry: a brief review of the literature and infection control implications. J Am Dent Assoc. 2004;135:429-437.
  8. Questions and answers about Marburg hemorrhagic fever. Available at: Accessed April 10, 2005.
  9. Harrel SK. The fragile immune system. Dimensions of Dental Hygiene. 2004,2(6):12-16.
  10. 2005 MRSA-Methicillin-Resistant Staphylococcus aureus. Information for healthcare personnel. Available at: Accessed April 10, 2005.
  11. Kohn Wg, Collins AS, Cleveland JL, et al. Centers for Disease Control and Prevention. Guidelines for infection control in dental health-care settings-2003. MMW Recomm Rep. 2003;52(No RR-17):16-17.

From Dimensions of Dental Hygiene. July 2005;3(7):28, 30, 32, 34.

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