Protect the teeth by sealants.
Sealants are like an insurance policy against cavities. Molars have tiny grooves in their surface which are difficult to clean with a toothbrush. Because food can collect in these grooves, bacteria also tend to live there. The result can be cavities which occur in spite of regular brushing.
Sealants are an easy solution to this problem. Usually recommended for children, sealants effectively seal the grooves in back teeth protecting them from decay causing bacteria. The result is fewer molar cavities in patients who have sealants.