NEW YORK (Reuters Health) - Your dentist may one day use a light beam to identify tooth decay just as it is getting started, according to researchers at Indiana University School of Dentistry in Indianapolis.

The new technology, know as quantitative light fluorescence, uses a high-intensity light beam to measure the loss of calcium and phosphate from a tooth, Dr. George K. Stookey reported. He presented his findings Sunday at the American Dental Association's meeting in Chicago, Illinois.

"By the time we can detect dental carries today--through X-ray and visual exams--they are often 2 years old or older," Stookey told Reuters Health. Quantitative light fluorescence "detects a lesion near inception," he added.

The areas of a tooth that show a loss of calcium and phosphate will alter the pathway of the light beam, Stookey explained. This information is then transferred to a computer image and saved for future reference.

During follow-up examinations, the technique is used again and the original image is compared with the newer image. When the newer image is superimposed over the original image, it shows the progress of decalcification, Stookey said.

This technique will also detect decay that develops around the margins of tooth restorations.

"One half of current restorations are replacements of previous restorations," Stookey said. Quantitative light fluorescence "will detect this decay earlier."

Early detection of tooth decay permits early treatment and in many cases may save a tooth or prevent the need for fillings. The best way to prevent cavities and tooth decay now is to use fluoride--be it in a toothpaste or preventative treatment, the researcher pointed out.