At 2:30 on a Monday afternoon in the summer of 1989, James Sharpe, a convenience store owner from Northampton, settled back in the dentist’s chair to have three teeth extracted.
AIDS was, presumably, the last thing on his mind, and he certainly had no risk factors for the disease.His dentist, Dr. Anthony E. Breglio, was not infected with the AIDS virus, quite unlike Dr. David Acer, the Florida dentist who was infected and passed the virus to six patients.
Furthermore, no other patients Breglio had treated earlier that day are known to have had AIDS.
Breglio practiced the type of infection control that most dentists used at the time – soaking his drills and other similar tools in chemicals, says Dr. Alfred De Maria, director of communicable disease control for Massachusetts, who looked into the case in 1991.
Today, Sharpe has AIDS, and he blames it on poor sterilization of dental equipment by Breglio, whom he is suing in Hampshire County Superior Court. Seven weeks after his dental visit, Sharpe developed flu-like symptoms; when other tests came back negative, he had an AIDS test. It was positive.
Whatever the outcome of the Sharpe case, which is expected to go to the jury this week, it has revived one of the nagging fears of the AIDS epidemic: that you can catch it just by going to the dentist.
How realistic are those fears?
Not very, say many infection-control specialists. And whatever the odds were in 1989, they are even tinier today.
In fact, if you’re looking for an excuse to avoid the dentist, you’d be better off with the old “My dog ate the appointment card” line.
But fear is a notoriously stubborn thing, and in the case of invasive medical procedures, not irrational. So like a diligent dentist picking around with that nasty little “explorer” tool, let’s take a close at the evidence.
With the Sharpe case still unresolved, there has been not one documented case in which a person has caught AIDS from dental equipment, even though Americans make nearly 500 million dental visits a year. If you want to calculate the risk ratio since the AIDS epidemic began in 1981, that’s zero cases over a denominator in the billions.
In fact, even if all 32,381 AIDS cases in which the mode of infection is unknown were actually caused by dental equipment – which is unlikely – the risk would still be vanishingly small.
Furthermore, Acer’s six patients are the only documented cases of AIDS transmission from a dentist infected with HIV. Federal health officials have never been able to pinpoint whether Acer cut himself and then accidentally exposed patients to his blood, failed to sterilize his equipment properly or infected his patients intentionally.
“There were some problems with his infection-control methods,” acknowledges Dr. Harold Jaffe, associate director for the HIV-AIDS National Center for Infectious Diseases at the federal Centers for Disease Control in Atlanta. “But we didn’t prove the route of transmission.”
The Acer case aside, there have been zero – count ’em, zero – documented cases of HIV transmission from infected health care workers to patients. And this holds true even after “look-back” studies involving 22,000 patients, though critics note that there were some methodological flaws in these studies.
By contrast, at least 40 health care workers have been infected by patients.
Still, there’s no question that, under pressure from nervous patients, dentistry been getting safer.
In 1989, when Sharpe believes he was infected, American Dental Association guidelines recommended sterilization by autoclave (which uses intense heat and steam under pressure), but said disinfection with chemicals, a less surefire germ-killing method, was also adequate, says Dr. Richard Price, a Newton dentist and ADA spokesman.
In 1992, the ADA toughened its stance, recommending that all metal instruments, including drills, be heat-sterilized after each use by autoclave, dry heat or chemical vapors. It also said chemical disinfection was no longer adequate.
This proved difficult, however, because many handpieces had to be taken apart to be sterilized or could not withstand heat, prompting some dentists to continue using chemical disinfectants instead.
Even today, some dentists don’t heat-sterilize as they should. The ADA’s own survey last year found that 92.5 percent of dentists heat-sterilize handpieces before each use – up from 25 percent in 1990 – but that still leaves 12,000 who don’t.
And some specialists, like David Lewis, a microbial ecologist at the University of Georgia, contend that only 50 to 80 percent of dentists heat-sterilize tools after each patient.
The technology has improved so much that dentists “can sterilize handpieces in toto now, without taking them apart, because manufacturers have made all the components heat-resistant,” says Price.
In 1993, the CDC issued its own infection-control guidelines, which don’t carry the force of law but are generally followed. These call for sterilizing with an autoclave, dry heat or chemical vapor all instruments that penetrate soft tissue or bone, like the burs used for drilling, as well as instruments that contact oral tissues, like mirrors.
Because the internal surfaces of high-speed handpieces and other devices can become contaminated, the CDC concluded that “soaking in liquid chemical germicides” is not acceptable infection control.
In practice, though, some dentists still use chemicals to sterilize equipment that is not heat-resistant, like the tabs that hold X-ray films.
“Cold sterilization with chemicals obviously only works for surfaces that the chemicals can reach – not for instruments with tiny nooks and crannies or hollow tubes – but it does work well for these solid surfaces,” insists Price of Newton.
“But things are evolving even as we speak, and as of this week, because of questions remaining in patients’ minds, I am doing away with cold sterilization myself.”
Increasingly, he adds, dentists are turning to materials they can use once and throw away, like devices used to polish teeth and the tubes that suck saliva out of the mouth.
So does this mean all risk of AIDS in dentistry is gone?
Not quite. A small risk will remain as long as there is any dentist out there who does not heat-sterilize or throw away after use everything that goes in your mouth.
That’s because, as Lewis showed in studies published in 1992 in the journal Lancet and last year in Nature Medicine, the AIDS virus can get into dental equipment and survive “up to several days” in the lubricating fluids inside the instruments.
Lewis, who testified last week for Sharpe, took blood from AIDS patients and mixed it with lubricants, then immersed the lubricants in a 2-percent solution of glutaraldehyde, a disinfectant. The virus survived.
“And if glutaraldehyde couldn’t kill the AIDS virus, then no chemical disinfectant used would be effective. Only heat effectively kills the AIDS virus in dental devices,” he said in a telephone interview. “But if the equipment is properly sterlized, there should be no concern.”
Dr. Sanford F. Kuvin, who also testified for Sharpe last week, charging that “dirty dentistry” was involved, agrees “there is no risk if the dentist or other invasive dental health care worker is HIV-negative and if sterilization is proper.” If not, he said, “there is a risk that’s somewhere between infinitessimal and small.”
So how can you tell if your dentist is doing the right thing?
“Ask questions and don’t stop until you’re satisfied,” advises Price, though for many patients, that’s easier said than done, especially with a mouth full of dental hardware.
Still, you could start by asking how much your dentist has spent to meet infection-control guidelines, including guidelines to protect dental employees. Many dentists have spent $ 24,000 a year to comply and may be quite happy to tell you so.
Ask if your dentist uses an autoclave, and if you’re in doubt, ask to see it. Then ask how often your dentist checks to be sure it’s working.
After that, you might as well relax because, as Price puts it, “There’s got to be some trust.”
Dr. Martin Hirsch, director of clinical AIDS research at Massachusetts General Hospital, agrees.
“I hate going to dentists,” says Hirsch, “but I think the risk of spread of HIV is infinitessimally low in that setting and people shouldn’t avoid dentists for that reason.”
Look and ask questions
Things to look for and ask about at the dentist’s office:
- Is the room clean and orderly, and do surfaces and equipment appear clean?
- Is the staff willing to answer your questions?
- Do the dentist and other dental workers practice “universal precautions,” including wearing gloves and other protective gear during your treatment?
- Are needles and other sharp items disposed of in special puncture-resistant containers?
- Is everything that goes in your mouth heat-sterilized or disposable? (If you’re worried about non-heat-resistant items like the gadgets that hold X-rays, ask. American Dental Association guidelines say it’s acceptable, though not preferred, to use chemicals to sterilize these.)
- How often is the autoclave machine checked? (Federal guidelines say it should be checked at least weekly.)
If you’re still worried, call the state Board of Registration in Dentistry (617-727-7368 begin_of_the_skype_highlighting 617-727-7368 end_of_the_skype_highlighting).