Below you can see a sequence of images showing how a lower jaw can resorb, once the teeth are removed.

Here you can see a lower jaw with teeth still in place. The right image 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.

These pictures show 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 pretty much on top of the ridge. This makes it often very painful to wear dentures, because they press on the nerve that exits there.

Here we see basically the same situation as above, just somewhat more severe. Notice how diminished the bone height is in the mid-jaw area, especially when compared to the very first jaw on top of the page.

This resorption process is a natural physiological process that takes place when there is no functional load (chewing) inside the bone via the roots of teeth. Dental implants are embedded in bone and will transfer the functional load of chewing into the bone and preserve it, preventing future resorption.