Summarize this article in one sentence.
There are not always obvious external signs that someone has a cavity. Because of this, a dentist may be the first person to notice. Because cavities can lead to further damage, it is important to see a dentist regularly to prevent cavities from going unnoticed. Go for a dental check up every six months and allow your dentist to see any changes. Some patients may have a mineralization defect of the enamel which allows cavities to form faster. This could be a sign you have a cavity. Toothaches; tooth sensitivity; mild to sharp pain when eating or drinking something sweet, hot, or cold; pain when you bite down all these may be a the sign of a cavity. If you are experiencing these things consistently, you should seek an oral health care professional. Visible holes or pits in your teeth, brown, black or white staining on any surface of a tooth can all be indications of a cavity; however, because everyone's mouth is different, it can be difficult to know. A dentist and other oral doctors are the people who are properly qualified to diagnose the problem and identify the stage of cavity development. If you think you see a cavity, you should get it checked out.

Summary:
Know that cavities may or may not have clear symptoms. Note pain. Look at your teeth.