The use of stereolithography in dentistry

Stereolithographic model of a lower jaw

Stereolithographic model of a lower jaw

Stereolithography is a technical process in which a work piece is constructed in layers with the aid of (screen) dots freely materializing in space.

The production of one – or several simultaneously-produced pieces – is usually fully automatic and based on data generated by a computer. In the video you see a device producing such work pieces; you can imagine the process as a printer, except that with stereolithography, the material is printed in three, rather than two, dimensions.

Here you see a stereolithographic model of a lower jaw; the data for the model was obtained from CT data. This patient was involved in a traffic accident and lost not just her teeth, but parts of her jaw as well. On the left, you can clearly recognize the missing bone; on the right, you can see that the missing part was replaced with a pink compound. Here is the front view once more. Using the stereolithographic model, an absorbable foil was formed, which will serve as a placeholder for bone substitute material.

Here you see an image of the mouth; you can recognize the lips, parts of the tongue, the base of the mouth, and the missing jawbone. First, the incision is determined with a marker; only then is the mucosa cut open and folded to the side, making the left over jawbone visible. After thoroughly removing the scar tissue and roughing the surface of the remaining bone in order to facilitate the growing in of the bone substitute material, the mold inserted.

The mold fits the defect precisely, because the stereolithographic model was obtained from the patient’s CT data. Now the bone substitute material is inserted below the foil, and the mold prevents the bone substitute material from shifting. Because of these placeholders, you don’t have to use your own bone blocks. Finally, the PLA foil is fastened to special pins in the bone, which are biodegradable. Now the wound is sutured so that saliva cannot enter it.

One week after surgery, the wound has healed well; one can still see the suture material. In the lateral image, you can clearly recognize the positive change in the facial profile resulting from the bone augmentation. After about six months, a CT check is performed and, if the bone has formed well, an implant is placed. The patient then receives artificial teeth again.

By means of such models, surgeries that were impossible only a short while ago can now be performed. Here you see a stereolithographic model of a patient with a malignant tumor. With this model, the surgery can be planned. The incisions, i.e., the so-called resection boundaries, can thus be determined in advance.

After the removal of the tumor, the face will be reconstructed with the exception of the eye. Such planning models help surgeons plan surgery in advance.

Click here to see the video: 3D Dental Imaging

 

This post is also available in: German

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