Fig.1 Fig.2

Dental Education Lecture: Why Does Tooth Crack?

There are several factors involving crack tooth.  It usually happens to a person over 30 years old.  It appears that crack tooth is sort of wear and tear. Crack happens more often when we just chew on one side of back teeth because we procrastinate in fixing the back teeth on the other side of the mouth. Second, the tooth has a big filling.  The tooth is weak.  Third, crack occurs most likely in people who love to chew something hard, such as ice and nut.  It is usually difficult to save the tooth with crack, particularly involving the root.

Mr. Hsieh (Xie, one of the most common Chinese last names, meaning Thanks) loves to chew dry bean.  Eighteen months ago, he shows up first time with complaint of pain in an upper right molar.  We do not know what happens.  Recently he returns with more severe pain.  Exam shows that there is a separate fragment (Fig.1 arrowhead) in the root (R) area of the troublesome molar.  The crown (C) seems to be alright.  The fragment is pretty loose.  It looks that the tooth needs to go.  Upon extraction, we find that one of two roots has split (Fig.2).  Two arrowheads in Fig.2 point to the junction between crown and roots.

In brief, to prevent crack tooth, try to avoid bad habit of chewing something hard when you are over 30 years old.  If you have a big filling, get a crown.  If you grind teeth at night, get a night guard.

Xin Wei, DDS, PhD, MS 1st edition 08/24/2010, last revision 08/25/2010