You mean cavities aren't just bad things that happen to good people?
The following information is intended to supplement, not substitute for, the expertise and judgement of your dentist, pharmacist or other healthcare professional.
Cavities are the demineralised areas, or the holes, that form in teeth as a result of a bacterial infection called dental caries.
This infection takes place when the normal healthy bacteria in the mouth are replaced by acid-producing bacteria.
The articles shown here should answer most if not all of your questions about cavities.