“Ouch! my tooth hurts!”, said one of my patients the other day during a routine examination. “Especially when I chew on my left side. Is it a cavity?” Sometimes it is a cavity that causes tooth to hurt. A lot of times it is not. A lot of times pain sensation, especially on chewing, is caused by micro-fractures in the tooth. During chewing, forces of mastication flex the tooth along those fracture lines and cause pain sensation. In the photos, you can clearly see fracture lines in several areas of the tooth. As time progresses, pain may become more pronounced. Quite often, this is followed by a separation of a portion of the tooth along those fracture lines. (tooth breaks). Quite often you get a relieve of pain after that. Some other times, you loose the tooth. (See my previous post).
There might be many reasons why teeth develop fracture lines: para-functional activities like grinding or clenching,
anterior open bite (only back teeth touching when fully closed), lack of anterior guidance (only front teeth touching during movement of lower jaw sideways or forward), and thus excessive stresses applied to back teeth during movement of teeth sideways etc.
Whatever causes these fractures, once tooth become symptomatic on chewing, you need to reinforce it before it breaks. That is usually achieved with onlays or crowns.