Root Development of Wisdom Teeth
The reason that our teeth come into the mouth is that the roots become longer. When wisdom teeth (the right (R) and left (L) in Fig.1) are impacted (for example blocked by 2nd molars, 2), their roots still keep growing and grow in the other direction. The root tips grow closer to a large nerve inside the lower jaw. If we have to extract wisdom teeth with longer roots, surgery will be more difficult and the nerve may get injured.
Fig.2,3 are blow-up pictures of Fig.1, the areas around the wisdom teeth. Arrowheads points the end of roots. White lines indicate nerve outlines. Fig.1 was taken when a patient was 17 years old.
Fig.4,5 show the wisdom teeth when the patient is 20 years old. The wisdom teeth are still impacted. As you may notice, the roots become longer and are closer to the nerve, as compared to Fig.2,3.
Fig.6,7 show the wisdom teeth of a 14-year-old girl. The roots are very short. One and a half years later, roots are longer (R, L in Fig.8).
L' in Fig.8 is a wisdom tooth of a 28-year-old lady. The roots are longer and more pointed in the end. Extraction is much more difficult than R or L.
Xin Wei, DDS, PhD, MS 1st edition 08/16/2011, last revision 08/16/2011