How are problems with wisdom teeth diagnosed?

Your dentist will check for signs of a wisdom tooth coming through your gum or crowding other teeth. You will have X-rays to find out if your wisdom teeth are causing problems now or are likely to cause problems in the future.

Source: http://www.webmd.com

What causes problems with wisdom teeth?

Wisdom teeth that are healthy and in the right position usually don't cause problems. You may have a problem if any of the following occur:

• Your wisdom teeth break through your gums only partway because of a lack of space. This can cause a flap of gum tissue to grow over them. The flap can trap food and lead to a gum infection.
• They come in crooked or facing the wrong direction.
• Your jaw isn't large enough to give them room. Your wisdom teeth may get stuck (impacted) in your jaw and not be able to break through your gums.
• They are so far back in your mouth or crowded that you have trouble cleaning around them.
• A cyst forms. This can damage the bone or roots.

Source: http://www.webmd.com