Fig.1	Fig.2
Fig.3	Fig.4	Fig.5

Dental Education Lecture: CT before Braces

Tiffany is thirteen years old.  Her teeth are pretty crowded (Fig.1).  She needs braces.  Upper right canine has not come out yet.  There is a space between the teeth #5 and 7, where the canine (#6) should be found.  In fact it is most likely above the tooth #5, underneath the gums.  It looks like a big tumor. 

In order to arrive at correct diagnosis and treatment plan for braces, CT is taken.  It shows that the tooth #6 is located above the root of the tooth #5 (Fig.2,3, three-dimensional images).

There are two types of treatment plans.  The first one is to move the tooth #6 to where it belongs (as indicated by arrow in Fig.1).   It is a lot of work.  Besides, the space between the teeth #5 and 7 is narrower than the width of the tooth #6 (Fig.2).  To increase the space for the canine, the front teeth may have to be pushed forward, creating a cosmetic problem.

The second treatment plan is to extract the tooth #5 and let the tooth #6 erupt by itself.  Why do we take out seemingly normal looking tooth #5 and keep unerupted tumor-like canine?  The CT pictures (Fig.2,3,4 (two-dimensional)) demonstrate that the root of the canine is longer than that of the tooth #5. 

In fact, the root of the tooth #5 is deformed, like a ditch, near the root tip (arrowheads in Fig.5) because of proximity of the tooth #6 against the root of the tooth #5 during their formation and eruption (arrow in Fig.4).

In brief, CT is an important diagnostic tool for complicated brace cases.  

Xin Wei, DDS, PhD, MS 1st edition 04/15/2011, last revision 04/15/2011