The tissues involved in implant procedures 29

Fig. 2-4. Immediately after tooth extraction, there is usually a good deal of alveolar bone separating the mandibular canal from the crest of the ridge. As the bone resorbs, the position of the canal will change and become closer to the ridge.

Fig. 2-5. Throughout life the gross anatomy and histology of the mandible changes. In a young child, the angle of the jaw is obtuse. It gradually changes until it is almost at a right angle in the mature adult. In old age, its angle changes once again. However, it is not the angle of the jaw that interests the implantologist but the altering position of the mandibular canal and the mental foramen. As can be seen, with advancing age and tooth loss the alveolar process lessens, leaving the mandibular canal and crest close together.

Fig. 2-6. A simulated skull of a 6-year-old child shows that the sinus floor and mandibular canal are quite distant from their respective alveolar crests because of the presence of unerupted teeth.