Dental Education Lecture: Cavity Progression

There is no pain associated with early cavity.  New cavity can also develop next to old filling.  Careful clinical and X-ray exam can reveal early and/or new cavity.  With improved oral hygiene, some of early cavity may stop or reverts to normal.  But this is not often the case.  Small painless cavity may develop slowly into a large one and cause severe pain all of sudden.  If in doubt, the doctor advises the patient to return to clinic for check-up on a regular basis.  However, the patient does not want to return during quiescent period of cavity development.  When pain occurs, we lose golden opportunity to treat more conservatively.

Two and a half years ago, a middle aged lady came to my office for regular check up.  Exam showed that a lower molar tooth had a silver filling (*, Fig.1).  Clinic note shows that there was black staining around the silver filling.  Something looked suspicious.  We told her to come back every 6 months for close follow-up.  

One early morning, she called my office, complaining severe pain in the evening and having hard time sleeping.  We retook two X-ray films (Fig.2 and 3).  This time we can see a dark shadow lower left to the silver filling.  Let us draw the outline of the enlarged cavity and the outline of nerve in the middle of the tooth (Fig.5 and 6).  How close the cavity is to the nerve.  It is apparent that germs in the cavity take free way to the nerve, causing severe infection.  Now we have to do more radical procedures to save the tooth, starting with root canal.

Let us go back to Fig.1 and look very hard for the early cavity.  It seems that there is a small area of shadow lower left to the silver filling.  The drawing in Fig.4 shows that the small lesion has quite a distance from the nerve.  No wonder that she did not have any pain at that time, more than two years ago.

Small painless cavity does not mean that you do not have problem.  You need to be dead serious.  Either improve your oral hygiene habits or get cavity filled.  Procrastination will lead to serious problems sooner or later.

In next lecture, we are going to show you how we get cavity using illustration.

Xin Wei, DDS, PhD, MS 1st edition 01/26/2009, last revision 02/11/2009