Cavities are detected during standard dental cleanings, and are typically quick to spot. During your appointment, your dentist will check your teeth for sensitive areas and utilize dental x-rays to assess what's going on. Using these methods, your dentist can tell you what type of cavity you have, what likely caused it, and what can be done to treat it. If a cavity goes untreated, it can result in severe toothaches and a dental infection, also known as an abscess.