Hopefully a good brushing and flossing routine will be a habit by the time those permanent teeth arrive. They will be used for a much longer time than baby teeth. Your dentist can bolster the home care and help prevent decay by applying dental sealants to those workhorse molars. The first permanent molars typically appear around age six.
If you are an adult who is prone to tooth decay, dental sealants might be right for you as well. Ask your dentist about them.