Sealants Dental Sealants are a plastic coating applied to the chewing surfaces of back teeth. Grooves in these teeth are so narrow that a toothbrush cannot fit into the spaces to remove plaque. Dental sealants prevent dental decay in the grooves. Sealants can provide 100% protection from dental decay or “cavities” on the chewing surface. Research has shown that when placed over very minimal dental decay, the decay will no longer progress.