A: Most dentists today recommend sealants -- a plastic coating painted onto your child's teeth -- to help protect them from cavities. While it's usually not necessary to seal most baby teeth (since they tend to be smooth and not as vulnerable to cavities), it can be helpful to seal some baby molars and any teeth that are especially grooved or pitted. Dentists do recommend sealing all permanent molars and most other adult teeth since studies show that kids with even one sealant application on their back teeth get half as many cavities as kids without them. Most sealants last three to five years; when your dentist notices that your child's sealants are beginning to wear away, he can simply reapply a new coating right over the old one. Although sealants are a wonderful preventive tool, pediatric dentists are quick to remind parents that they should be seen as extra protection against cavities, not a replacement for regular brushing and flossing or a free pass to eat junk food. The only real downside to sealants is that they don't come cheaply, so check with your insurance company to see if they're covered.