Why can't I just have a metal plate instead of bone?

When a segment of the lower jaw is removed, the two remaining halves must be reconnected to restore the bite and maintain facial form. This is usually done with a metal plate and screws to hold the segments together. So why bother with adding bone? There are two main reasons we will explore here.

First, the plates are made of titanium. Why? Because the bone loves titanium and tolerates it very well. Allergies to this metal are exceedingly rare. The titanium plates are about 3mm thick and strong, yet they are brittle. This means that over time, the stress on the plate from chewing forces will cause the plate to break. A broken plate requires surgical removal and placement of a new plate. The new plate is just as susceptible to breaking as the first plate. Adding bone to the defect allows the forces of chewing to be shared by the bone so the plate is much less likely to break. I have seen multiple cases where a plate without bone breaks in less than a year.

Second, your soft tissue does NOT attach to the plate. The soft tissue (muscle and skin) ignores the plate and shrinks inward towards the mouth after the jaw bone is removed. Eventually the plate becomes exposed and sticks out through the skin. However, the soft tissue WILL attach to bone. So putting bone next to the plate prevents the skin from contracting inward and prevents the plate from becoming exposed through the skin.

Then why did my surgeon recommend just a plate?

There are rare cases where a plate without bone might be a reasonable option. Sometimes this is done for elderly or unhealthy patients that are just not able to safely tolerate an additional bone grafting procedure. The risks of plate problems must be weighed against the risks of longer anesthesia. However, if the plate develops problems, additional anesthesia will be required to fix it.

For patients with no teeth, a plate without bone is at less risk of fracture since the chewing forces are very low. On the other hand, a patient with all their remaining teeth is at much higher risk of breaking their plate if there is no bone to share the forces of chewing.