Dentists: eschew chewing aspirin.

Chewing aspirin or even letting the tablets dissolve in the mouth can seriously damage teeth, a report of two such cases suggests.

Dentists have long discouraged patients from chewing aspirin since it can irritate the gums and cause mouth ulcers--what some dentists call "aspirin burn." But chewing aspirin had never been directly implicated in tooth damage.

Researchers at the University of Maryland Dental School in Baltimore have now documented such damage in two patients who chewed aspirin regularly to relieve headache pain. One patient, who chewed four to eight aspirins a day for more than a year, experienced tooth pain and damage to teeth throughout her mouth. The other, who chewed six aspirin tablets daily for 6 months on one side of his mouth, experienced severe enamel erosion in the molars there.

In these patients, "we found no other reason" for the tooth damage, says dentist Edward G. Grace. The study appears in the July Journal of the American Dental Association.

Most drugstores sell chewable aspirin. Whether such tablets would cause tooth damage if chewed but then promptly washed down with water remains unknown, Grace says. These two patients routinely permitted the aspirin particles to linger in their months, he says.--N.S.