J.V.
H., I am a dental hygienist..so I have some "professional" advice. They should at least brush EVERY SINGLE NIGHT!!! Saliva is one of the things that keeps plaque in check..this drops by 30-50 percent production while sleeping.
So they will have a a full day's amount of plaque and then the saliva drops. It is a double whammy! If you have no dental insurance sometimes colleges that offer dental programs (both dental hygiene and dental) offer appoints at a very low rate (like 20 dollars). I know in my dental hygiene school also offered "sealants". Sealants are a liquid (kind of like plastic). We put it in the cracks on the chewing surfaces and cure it (make hard) with a special light. This only is beneficial to teeth that don't have decay yet. They might be a little young for this now but as soon as you can get them! They are one of the best preventive measures against decay on chewing surfaces. The cracks on the top of teeth are so small even a toothbrush bristle is to big to get into them. This type of decay is 78% of children decay areas. But you and the kids need to brush EVERY SINGLE NIGHT!
If my husband was not on board I would let him know when they need to go to the dentist at a young age, and suffer a possible fear of the dentist for the rest of their lives, he will have contributed to that. People are often under the impression that baby teeth are throw away teeth....just get them pulled new ones come in..without writing a three page answer as to why this is not true..they serve many many other functions. Plus if your children don't develop good oral hygiene habits now they are not as likely to take care of the permanent teeth either. Hope this helps!