The best way to treat is a cavity is to prevent it from forming. The starting points are diet, hygiene, and adult supervision.
Sugary foods and drinks should be limited or avoided. But don't be fooled: Fishy crackers, sports drinks, granola bars, and other everyday foods also can cause cavities.
It is thought that once a child can tie their shoes they have the coordination and ability to brush their own teeth. This usually occurs around the age of 7. Some kids need supervision long after this.
Use fluoridated tooth paste in controlled quantities. The size of a pea is a good guideline. Once a child can rinse and spit, fluoridated mouth rinse can be introduced.
There is no substitute for parental supervision. Some kids like to brush their teeth, others kid need to be observed, step by step, as they complete the brushing.