Bone Resorption

Bone Resorption is a very natural phenomenon. The bones in our bodies are not static - they are dynamic! Bone will strengthen or weaken, depending on the amount of "load" or "strain" that is placed on bone. The more "load" is placed on a particular bone, the more it will mineralize (become denser) and stronger. On the other hand, if not enough "load" is placed on a particular bone, it will diminish in density, but also in size. A broken arm that had a cast on it for several weeks will have bones that are somewhat diminished in size and strength, until the arm is utilized to normal function again.

The same phenomenon is observed in jaw bones. Teeth are the "conductors" of load into the jaw bones (jaw muscles are the "generators" of the load). If teeth are missing, no load is being transmitted to that part of the bone and, consequently the bone in that area will diminish (resorb).

Below are a series of images showing the progression of bone resorption as a result of tooth loss as well as the length of time teeth were absent:

Here you can see a lower jaw with teeth still in place. The right shows the frontal view and the left shows the side view

These two images show a lower jaw with recent loss of the front teeth and previous loss of the back teeth. Notice how the bone height has decreased somewhat in the back area, as compared to the jaw above.

This pair of pictures shows a lower jawbone that had been toothless for some time. The little ‘holes’ circled in red are foramina (nerve and vessel exit holes) which you can use as a landmark to see how the vertical height keeps diminishing as we continue.

This is a jaw that has been longer without teeth than the one above. Again, notice the relative height of the foramina (red circles). They are actually fixed anatomical points. So when it seems like they are ‘creeping up’ towards the ridge, it’s because the jaw resorbs from the top of the ridge down.

This jaw on the left and right had been toothless for quite some time (possibly several decades). Notice how much the vertical dimension has decreased and how the foramina (red circles) are pnow ‘on top’ of the ridge. This makes it often very painful to wear dentures, because they press on the nerve that exits in that location.

Most Dental Implants are devices, which are firmly embedded in bone and will therefore transfer the functional load of chewing into the bone. This will prevent further bone resorption and preserve, if not strengthen the bone density in that particular area of the jaw bone.