Dental Education Lecture: Why Do We Need Crowns?





Mrs. White had toothache in her molar tooth several years ago and had to get root canal (Fig.1 arrowhead) and silver filling (A, amalgam) done.  After the initial treatment, severe pain was gone.  She hesitated to return dental office to get a crown for protection.  One day, she felt sudden severe pain with the molar tooth while she was having a meal.  Casual look at the tooth from the front reveals a barely noticeable crazing line (black arrowhead, Fig. 2).  When you look at from the top (red arrowhead, Fig.2), cracking line is more obvious (2 arrowheads, Fig.3).  When we lift the smaller portion of the tooth, you can see that the tooth is completely split into two halves (Fig.4).  It is obvious that the tooth is non-salvageable.  What a pity.

When our back tooth is weak due to a large cavity, especially after root canal, we should routine crown the tooth for full protection.  However, we may not need a crown for a front tooth after root canal, if it is pretty intact.  Our back teeth sustains enormous biting force.  The chance of tooth crack is high for back teeth.

In next lecture, we will discuss crown and bridge application.

Xin Wei, DDS, PhD, MS 1st edition 02/12/2009, last revision 02/13/2009