Dental Education Lecture: Upper Wisdom Tooth

As we have eaten finer food for many generations, our jaws have become smaller so that wisdom teeth cannot erupt into normal position.  They cause a lot of discomfort.  In some cases, we need to extract troublesome wisdom teeth as soon as possible.  In this lecture, we will discuss what will happen if we keep initially apparently harmless upper wisdom teeth.

Fig.1 shows one side of upper and lower 1st, 2nd, and 3rd molars.  The 3rd molars are also called wisdom teeth.  Most of us do not clean the back teeth very well.  We may not make effort to brush the last tooth or do not floss there.  It is fairly common to have cavities in wisdom teeth.  It is worse to have cavities between last two molars (black spot, Fig.2).  However, it is not easy to do filling in the back of mouth (shaded area, Fig.3).  The dentist may not completely close the gap between the last 2 teeth (arrow).  Food is easily dislodged there (black spot).  To solve this problem, we either need to have the 3rd molar extracted or fabricate more sophisticated restoration called inlay or onlay to close the gap.

Fig.4 demonstrates missing lower 3rd molar.  The upper 3rd molar has no stop and starts to grow downward (arrow).  After several year, the upper 3rd molar overgrows, i.e., elongates.  It pinches the lower gums, causing ulceration (arrow, Fig.5).  Elongation of 3rd molar leads to loose contact between the last 2 teeth and food impaction (black spot).  Wisdom teeth may be oversized or teeny tiny (3, Fig.6).  Size abnormality is usually associated with food impaction (black spot).  The best and most likely only treatment is to extract the wisdom teeth.  After extraction, the 2nd molar usually do not tilt backward.  Our teeth have tendency to shift forward, but not backward.  We will discuss lower wisdom teeth next.

Xin Wei, DDS, PhD, MS 1st edition 01/17/2009, last revision 03/20/2010