Dental offices should have basic TB control programs
Many offices lack protection from transmissions
Although health officials anticipate that the new tuberculosis standard from the Occupational Safety and Health Administration (OSHA) won’t consider dental facilities to be a high-risk environment, dental schools and offices should implement TB programs that include risk assessment and annual PPD testing, they say.
"My understanding is [OSHA officials] will pretty much leave dental offices out, unless they are in one of the five designated areas, so the standard won’t concern the majority of offices," says Jennifer Cleveland, DDS, a dental officer and epidemiologist for the Centers for Disease Control and Prevention’s division of oral health.
With only one documented case of TB transmission in a dental facility, the CDC considers dental facilities at low risk for the spread of the disease.1 OSHA is expected to model its standard, due out this summer, on the CDC’s 1994 TB guidelines, which designated five workplaces at high risk for TB, including health care facilities.
While OSHA probably won’t be making routine visits to dental offices, Cleveland notes that the CDC recommends that all dental settings conduct an initial baseline assessment of their risk for TB and develop a written TB infection control protocol corresponding to their level of risk.
"Regardless of what OSHA says, I think they should do everything we recommended," Cleveland tells TB Monitor. "For 95% of dental offices it is mostly administrative controls, and it is not costly it doesn’t require any respiratory protection."2 (See highlights of CDC recommendations for dental settings, p. 89.)
At a minimum, dental facilities should provide regular education and training on TB infection and control, as well as baseline testing of new employees and possibly annual PPD testing for all staff, Cleveland says. Baseline testing is necessary to obtain an accurate assessment of a setting’s risk for TB, she adds.
The CDC bases the extent of TB program controls in health care facilities on five risk levels, ranging from minimal to high. However, the guidelines were based on hospital settings and, therefore, are not as easily applied to dental settings, says Denise Murphy, DPH, associate professor of comprehensive care and applied practice administration at New York University College of Dentistry in New York City. In a recent article in the American Journal of Infection Control, Murphy highlights obstacles encountered when trying to apply the CDC TB guidelines to a large dental center.3
Conversion rates hard to measure
One of the biggest obstacles is the difficulty in assessing the level of risk within a dental facility. The risk is determined by a TB profile of the surrounding community, the number of patients with active TB admitted to a facility, and results of employee PPD screening.
Unlike most health care settings, most dental facilities don’t have an adequate history of PPD testing to establish baseline rates, she says. Published reports of PPD conversion rates among students and staff at dental teaching facilities are sporadic and vary widely from 2% to 40%, Murphy notes. At the time the study was implemented in 1995, the majority of accredited dental schools responding to a survey had not yet implemented periodic screening for TB among their students 58% had no information on student PPD conversion rates, and 29% had either no data available at the time or were unwilling to share it, she adds.
Studies of PPD conversion rates in dental students and practicing dentists have found them to be somewhat higher than the general public 7% to 8% compared with 4% to 6%. At New York University College of Dentistry, a facility that houses 500 dental treatment units, the conversion rate among third-year dental students was more than 10%, suggesting an even higher risk than previous estimates.
However, Cleveland, who helped design the study, says the figure is misleading because two-step testing was not implemented, and many students are foreign-born. "The results are hard to interpret because it would be hard to know who was not previously infected," she says.
Despite the high conversion rate, no case of active TB has been reported in students or staff at the facility, Murphy says. Based on these two measures, it is difficult to assess the risk within the framework of the CDC guidelines, she adds.
Compelled by ethical obligations alone, the facility developed a TB control program several years ago. It includes regular staff education on how to identify TB in patients, baseline PPD testing of new employees, and annual PPD testing.
"We didn’t wait for an OSHA standard because we thought that taking a proactive approach was important for us to do," Murphy says.
The facility has been providing regular training of staff and students on the signs and symptoms of TB, as well as socio-economic factors of high-risk groups. At minimum, dental settings should emphasize the need for conducting complete medical histories of patients initially and asking follow-up questions on return visits, she says.
"With the OSHA standard, my guess is that education will be an important strategy," she explains. "It can be effective as long as it is done by someone who is trained and is done on a regular basis because everyone becomes lax over time."
Concerns over treating active TB patient
Since publishing her article on how to implement CDC guidelines in a dental setting two years ago, Cleveland has received few complaints from dental facilities. The American Dental Association had provided strong input while the guidelines were developed, primarily over concerns that dental facilities might be saddled with the respiratory protection regulations put on health care facilities, Cleveland says. Now that dental practitioners have had a chance to digest the CDC guidelines, the biggest concern has come from rural dental clinics, which often don’t have nearby dental facilities that can treat active TB patients, she says.
"How they find a referring facility is a reasonable concern," she says. "But my response is that there are very few dental procedures for which you cannot give palliative care; so in reality, there are few occasions that you will have to perform emergency services on someone who you are not sure about their TB status."
Most patients can delay dental treatment with proper medication, says James Cottons, DMD, MS, director of the division of oral diagnosis and oral medicine at the University of Texas Health Sciences Center in San Antonio. Patients who come into an office exhibiting the three classic symptoms of active TB heavy coughing, night sweats, and weight loss greater than 10% are immediately given a surgical mask to wear and are referred for medical attention, he says. In almost all cases, dental treatment can be deferred until a patient is treated and has three negative sputum tests, he adds.
Because dentists and dental hygienists wear surgical masks for most procedures, their risk of occupational exposure is extremely low, Cottons says. The one documented case of occupational TB transmission involved two HIV-positive dentists treating immunocompromised patients in a hospital. The dentists shared offices and were exposed to each other day after day. Most TB transmission requires prolonged exposure, much longer than a typical dental visit, he adds. With recent approval of the new N95 respiratory masks for TB protection, the cost of adequate TB protection is less than $1. But dental facilities are unlikely to switch from plain surgical masks because they cost little more than a dime, Cottons says.
From his consulting work with dental teaching facilities, Cottons estimates that most of the nation’s 55 dental schools and 200 dental hygiene schools are conducting annual PPD screening of students and staff. "Although it’s not yet mandatory, I am surprised at the high percentage of dental education institutions that are doing annual PPD testing," he says.
One issue facing dental offices and related to TB control is the need for improved ventilation, Cottons says. Submicron particles, including TB, can be transmitted through the air by aerosolizing procedures, such as drilling and scaling. Many dental facilities are located in multi-office buildings that share the same ventilation system, he says. With mounting federal concern over the production of bioaerosols in closed areas, dental facilities are under pressure to improve ventilation systems, he says.
References
1. Cleveland J. Multidrug resistant TB in an HIV dental clinic. Infect Control and Hosp Epid 1995; 16:7-11.
2. Cleveland J, Gooch B, Bolyard E, et al. TB infection control recommendations from the CDC, 1994: Considerations for dentistry. JADA 1995; 126:593-600.
3. Murphy D, Younai F. Obstacles encountered in application of the Centers for Disease Control and Prevention guidelines for control of tuberculosis in a large dental center. Am J Infect Control 1997; 25:275-285.
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