The Mouth: A Diagnostic Tool

It is no surprise that certain systemic diseases, like cancer, osteoporosis, coronary artery disease and certain viral infections are becoming more prevalent amongst the general population. Whether this is due to unhealthy diet, genetics, age, or environmental factors like smoke and pollution, more are being diagnosed with these and other lethal infections. Regardless of the source, many individuals are reluctant to see their doctors on a regular basis, which may not only prevent diseases, but allow them to be treated in an earlier and more curable stage. People are failing to turn to their physicians, so perhaps a visit to the dentist could be an alternative. Recent evidence shows that there may be new screening technology for the oral cavity that could possibly predict which patients are at risk for developing these diseases. Minimally invasive, inexpensive, and painless screening techniques, that are currently demonstrating promising results in clinical studies, may be the diagnostic tool of the future.

According to the American Cancer Society, the second leading cause of death among American women today is breast cancer. In order to detect cysts, calcifications and tumors within the breast, typically women over the age of 35 make a trip to their OBGYN to receive a yearly mammogram. However, Chyke A. Doubeni, M.D., M.P.H., of the University of Massachusetts Medical Center claims that, "Despite their [women] significant risk for development of a new breast tumor, even women who comply with a recommended yearly mammogram gradually fall by the wayside over the years." On the other hand, in a recent experiment at the University of Texas, Dr. Charles F. Streckfus D.D.S., may have discovered an alternative method for diagnosis. He simply examined a swab of saliva for salivary protein levels, which he claims have the potential to assist in diagnosis of breast cancer, and the ability to monitor tumor response during treatment. The study revealed that breast cancer patients tend to have higher levels of salivary proteins than healthy patients, that ultimately decrease once chemotherapy is initiated. Though this method has not yet been approved by the FDA, it is still an easier process for the patient and the practitioner. Until this new technology receives approval, in collaboration with mammography and blood work, salivary protein analysis may enhance the diagnostic acumen of the medical provider.

An analysis of the saliva may eventually help gynecologists to also detect other disease states. A study conducted at the University of Buffalo concluded that the prevalence of gum-disease causing oral bacteria has been linked to oral bone loss. In a controlled setting, postmenopausal women that were part of a larger investigation involving risk factors for osteoporosis and oral bone loss (see picture to left), were examined for specific periodontal pathogens, mainly P. gigivalis and T. forsynthesis. These two pathogens were found to infect 15.1 percent and 37.9 percent of these women. In addition, two other pathogens, P. intermedia and C. rectus, were found in 43.4 percent and 17.4 percent of women. If indeed these oral pathogens are related to bone loss in the mouth, it is conceivable that this may prove to be an easy, reasonably priced, and risk free test that may help in the diagnosis of systemic osteoporosis. It is well known that obese women compared to women with normal BMIs have a lower risk of developing osteoporosis due to effects of estrogen and weight bearing on bone preservation. However, this study also found that the greatest risk for oral bone loss was found in overweight women, supported by a three-fold increase. These seemingly contradicting discoveries only support the fact that further research needs to be done to elucidate the seemingly conflicting results. Since the cost of the current bone density test used by gynecologists is so significant, if further investigation of this new diagnostic tool could prove to help predict systemic osteoporosis, health care costs could be decreased dramatically.

Salivary analysis could also help infectious disease specialists diagnose viral infections. Although typically these viruses are found through examination of blood samples, Farmer, Clewley, Griffiths, and Johnson of the U.S. National Institute of Health claim that, "The sensitivity of the saliva Murex GACELISA is the same as the routine serum testing assay." For example, salivary IgA levels tend to decline as an HIV patient becomes symptomatic. Therefore, it may be that the detection of IgA antibody to HIV (see picture to right) in saliva may indicate the progression of the HIV infection. Similar studies have used saliva samples as a successful tool for diagnosis of hepatitis A and hepatitis B, based on the levels of IgM antibodies in saliva. In particular, it has been found that low levels of IgM are associated with vaccine-induced immunity. Just as the comparison of serum and saliva levels of antibody to HIV have been directly correlated, so have the levels of antibody for hepatitis (sensitivity = 98.7% and specificity = 99.6%). Since it has been discovered that in certain cases saliva and serum analysis are equally effective in the diagnoses of some diseases, this new technique may be advantageous. This needle-less method of analysis is not only simple and cost effective, but it is also beneficial to those patients, like hemophiliacs and drug users, who have difficulty in accessing peripheral blood.

Saliva samples are also being used to predict and monitor drug and hormone levels, certain autoimmune diseases, and hereditary diseases like cystic fibrosis. Still, many physicians are hesitant to believe that it could ever truly be considered a valid method for accurately predicting systemic diseases. For instance, Irwin Mandel, a professor emeritus of Columbia University, believes that, "Saliva doesn't have the drama of blood and the salivary glands are only lowly excretory organs." Although plenty of further research is necessary to make this new diagnostic tool legitimate, it is still very encouraging to believe that in the very near future, health care providers may have a painless, efficient, and cost effective way for detecting several of today’s most common diseases. After all, swabs of certain body surfaces that were at one point thought to be unreliable have proven to save lives, and the classic example is George Papanicolaou’s Pap Smear.