Fluoridating water supplies may help older seniors keep their teeth, a new study from Ireland shows.

Fluoridation has long been used to protect children from cavities, but the approach also helps older people maintain dental health, The New York Times reports.

But the study, by researchers at the dentistry school of Trinity College Dublin, found fluoridation had no effect on overall bone density. The findings are based on surveys of almost 5,000 adults older than 50.

Those who lived in areas with fluoridated water were more likely to report having all their teeth, the researchers found.