Dental Education Lecture: When to Remake Crown?

We need to remake a crown when it is broken or it has new cavity underneath.  Since the crown margin is very close to the gums, it is extremely difficult to fix cavity with simple filling.  The cavity may be very deep.  Only removing the whole crown can the dentist get rid of the cavity completely to prevent cavity formation again.  Today we use an example to show the 2nd reason to replace a crown.

Mrs. Li is a veteran dental patient.  Veteran here means that she has had a lot cavities before and therefore a lot of experience in dental treatment.  When she came to my office two years ago, she complained that bad odor (like a cavity) was from an old crown in the upper right area.  X-ray examination showed that the tooth #3 in upper figure has a crown.  There was a gap between the crown and the tooth (two arrowheads), most likely caused by a new cavity.  The crown needed to be replaced.  The tooth #2 had had root canal and filling.  A new crown should be made for it.  The tooth #4 had a cavity delineated by three arrowheads.  A filling (F) would be needed.

We fixed these three teeth together (Figure in the bottom).  During the procedure, we found that the tooth #3 had a new cavity as Mrs. Le predicted.  Since crown cementation, the bad odor has never been an issue for the upper right area.

Xin Wei, DDS, PhD, MS 1st edition 11/18/2009, last revision 04/19/2010