INTELIHEALTH - Dental sealants do protect teeth from decay, say Finnish dentists – but not all the time.

The dentists kept track of groups of children who visited health centers in two cities in Finland: Vantaa and Kemi. They wanted to find out what happened to the children's first permanent molars. These teeth also are called 6-year molars, because they come in when a child is about 6 years old.

Some of the children's molars were protected by plastic dental sealants. Other molars were not.

In Vantaa, unsealed molars were more likely to need fillings than sealed molars. But in Kemi, the opposite was true. Sealed molars needed fillings more often than unsealed molars.

The dentists say this may be because sealants are used differently in the two cities. In Vantaa, sealants are offered to all children. In Kemi, sealants are given only to children at very high risk for tooth decay. So in Kemi, the children with sealants also were the children most likely to get cavities.

Because sealants may fall off or wear away, they can't completely protect teeth from decay. But they are easy to put on and don't cost much. Most dentists recommend them.

The dentists who did the study are from the University of Oulu. The study appears in the January issue of the Journal of Dentistry.