UB Study Indicates Routine Dental X-Ray May Be A Valuable Tool In Stroke Prevention

ORLANDO, FLA. -- The dentist's office may become the new first line of defense in the battle to prevent stroke.

Dental researchers in the University at Buffalo School of Dental Medicine are the first to show, in a general population, that a standard dental X-ray taken on new patients to establish a baseline picture of dental health also can detect potentially dangerous calcium deposits in the carotid arteries, the large vessels on both sides of the neck that supply blood to the brain.

In a review of dental X-rays, they detected calcifications in the carotid arteries -- a sign of advanced atherosclerosis, a major cause of stroke -- in 5 percent of the dental X-rays of more than 2,700 new patients in UB's dental clinics. All of the patients were told of the findings and referred to their personal physician for follow-up.

Results of the research were presented here today (Friday, March 21) at the annual meeting of the International Association of Dental Research. They will appear in the June issue of the Journal of the American Dental Association.

"It was a fortuitous finding," said Laurie Carter, D.D.S., Ph.D., a radiologist and associate professor of oral diagnostic sciences in the UB School of Dental Medicine. "If we can see this on a routine dental film, it will be a powerful tool for detecting patients who are at risk but don't know it."

Of the 550,000 people who suffer a stroke annually, most have no symptoms, Carter noted. "If there is anything we can do to protect these people, we have to do it. That is the aim of this study."

Carter decided to investigate the potential of using a type of dental X-ray called a screening panoramic radiograph to detect carotid calcification after reading a journal article from 1981 that reported such a possibility. A panoramic radiograph is a wide-angle frontal X-ray taken during a patient's first visit to establish the initial condition of the teeth and surrounding bone and at periodic intervals thereafter as needed. The article prompted little follow-up outside of military veteran populations.

The UB investigation involved reviewing the screening panoramic radiographs of 2,752 new patients at the UB dental clinics, obtained between August 1994 and July 1996. Calcifications in the carotid arteries were detected in 143 patients, or about 5 percent of the sample. Two thirds of this group were women, with a mean age of 65 years. Findings showed that 40 percent of patients with calcification had the finding in both carotid arteries.

While most of these patients had no stroke symptoms and only three had a history of transient ischemic attacks, or mini-strokes, many had several risk factors for atherosclerosis. Interviews with patients who had carotid calcifications determined that 35 percent were obese; 34 percent had high blood pressure; 20 percent were taking blood thinners; 8 percent had diabetes, and 11 percent were smokers. Several patients with calcifications had more than one risk factor for atherosclerosis.

Carter said the presence of calcification confirms there is a problem, but doesn't define the extent of the problem. "The calcification may be confined to the arterial walls and may not be blocking the vessel," she said. "But when we find it, patients should be referred to their physician immediately for a full work-up."

Individuals should not consider it strange that their dentist would be the first to warn them about stroke, Carter said.

"Many systemic diseases make their presence known first in the oral cavity," she added. "Dentists are really physicians of the head and neck areas; that is their training. We are responsible for everything on a panoramic dental film, not just the teeth."

. Carter and her colleagues are currently setting up two studies to determine the sensitivity and specificity of the X-ray findings. In one study, they will conduct ultrasound and cholesterol screening on patients with and without carotid calcification findings. In another, conducted in collaboration with UB's neurology faculty, they will take panoramic dental films of stroke patients to look for the presence of calcifications after the fact.

"Once we establish the sensitivity and specificity of the radiographic evidence, I would expect significant collaboration with the medical community," Carter said. "Evaluation of films already obtained in the course of routine dental care may prove to have significant public health utility in the diagnosis of patients at risk for stroke."

Dental students Angela D. Haller and Ann D. Calamel assisted in the research, which was supported in part by training grants from the National Institute for Dental Research.