Post and Root Fracture
When our tooth is badly broken down, it may need post(s) (Fig.1: P) to keep a crown (2, 2nd molar) in place after root canal (R). If we chew heavily for several years, the root with a post has tendency to break.
Fig.2 is a magnified image of Fig.1. This molar in fact has two posts (P1, P2) associated with two of three roots. The outlines of these two roots are drawn in pink and yellow.
One year and a half later, new X-ray is taken (Fig.3). The root (pink) associated with P1 appears to have been shifted! Careful exam of this molar reveals that a piece of tooth structure is sticking out (Fig.4 *). The tooth cannot be saved.
First the fragment is removed (Fig.5: F). The remaining tooth is out next (Fig.6); a post is also sticking out (*). When the fragment is placed back to where it belongs (Fig.7: F), we may realize the close relationship between the post and root fracture.
After extensive dental treatment such as placement of a post and root canal, a crown can protect our tooth (the portion sticking outside the gums). But the crown does not protect our roots. To prevent the disaster, we should change our chewing habit. Do not chew something hard, such as ice, nuts, bones and crab legs. Our heavily treated tooth is in fact weak.
Xin Wei, DDS, PhD, MS 1st edition 05/10/2012, last revision 09/07/2012