Improper Implant Placement

One of the errors made by inexperienced or inadequately trained implant dentists is the improper placement of the dental implants. We see this too often in cases that come through our door. Read here about improper dental implant placement, and then read our page about proper dental implant placement.

Here is an example of a patient who came to us complaining of shooting pains in her jaw. First, here is the radiograph in sagittal (side) view:

improper-implant-placement

The darker space between the arrows is the nerve canal that runs through the lower jaw. Notice how it is relatively narrow and of a uniform width further back in her jaw, and when it gets close to the implant, it becomes considerably wider. This is because the surgeon, possibly from a lack of experience, may have thought that avoiding direct impingement on the nerve was good enough. But if there is less than two millimeters of bone between the implant and the nerve canal, it can cause inflammation, as indicated by the widening of the canal in this scan.

Further diagnostic information was needed, however, before undertaking surgical intervention. Dr. Arthur Chal ordered an MRI of the lower jaw, and had it evaluated by his radiology partner, Dr. David Hatcher. Here is the MRI:

improper-implant-placement-MRI

This MRI image shows that the nerve canal is expanded, and Dr. Hatcher has indicated on the image the inflammation detected within the nerve canal. Imagine if you bruised your arm. It would turn red and swell at the point of the bruise. The same thing has happened here to the nerve, causing pain.

Read more about Dr. David Hatcher‘s expertise and the long-standing professional relationship between Dr. Chal and Dr. Hatcher.

Dr. Chal also ordered a CAT scan. Here is a cross-sectional frontal view, taken from the three-dimensional CAT scan:

improper-implant-placement-2

These images are cross-sectional images taken at one-millimeter slices of the lower jaw. You can see the dark circle in the jawbone below the implant- that is the nerve canal. There are only about 1.5 millimeters of bone between the implant and the nerve canal, as indicated by the red arrow. This is in the risky zone where the patient can experience nerve inflammation. And she was indeed complaining of sharp, lancing pain on this side of her jaw. 2 to 3 millimeters of bone is desirable to provide an adequate safety zone in order to avoid this problem.

Another problem is indicated by the yellow arrow, and that is inadequate bony support. Note than only about a third of the implant is solidly encased in bone. This implant is approximately 12 millimeters long, but, on the right side of the image, we show only 4 millimeters supported by bone. Placement like this will cause a poor long-term prognosis for the stability of the implant.

A dental implant in this situation is susceptible to movement, which can loosen it and contribute to inflammation and infection. We call this inflammation around an implant “periimplantitis,” and it can eventually cause the loss of the implant.

The patient’s diagnostic records gave a consistent picture of serious inflammation caused by a violation of the safety zone between the implant and the nerve canal. The implant was surgically removed, and the pain disappeared.

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