Surgeons at the University of California (UC) Davis School of Veterinary Medicine can now regrow an almost complete lower jawbone.
The procedure can be performed as long as there is enough healthy bone remaining on the rear of the lower jaw, on each side of the mouth, and has now been successfully performed on three dogs in the past year.
During the reconstructive procedure, surgeons remove loose bone fragments from an injured area or a full section of the jawbone from a cancerous area, then screw a titanium plate into place on the remaining bone, on each side of the removed area.
A sponge-like scaffolding material, soaked in a bone growth promoter known as bone morphogenetic protein, is then inserted into the space where the bone was removed. The growth-promoting protein stimulates remaining jawbone to grow new bone cells, eventually filling the entire defect and integrating with the native bone.
On a radiograph (x-ray), the formation of new bone can be detected by two weeks post-surgery. By four to six weeks, the majority of the defect is filled in with new bone. By eight to 10 weeks, the new bone is fully formed and integrated with the native bone, forming one continuous mandible. The procedures, to date, have all been successful.
One of the recipients of the latest advancement of this procedure is Hoshi, a 10-year-old female collie diagnosed with squamous cell carcinoma, which had required the removal of diseased bone from the front of Hoshi’s mouth.
Oncologists examined Hoshi and found the cancer had not metastasized into her lungs or other areas. A CT scan confirmed removal of the entire front part of the jawbone (extending back on both sides of the mouth) was necessary to completely remove all the affected tissue.
From the CT scan, UC Davis Biomedical Engineering TEAM facility printed a 3D model of Hoshi’s skull to help Dentistry and Oral Surgery Service surgeons plan the surgery.
Using the 3D printed skull, the surgeons were able to contour and fit the titanium plate needed to form Hoshi’s new jawbone before the surgery. This preparation shortens the surgery time, creating a safer environment for any animal under anaesthesia. Following the procedure, another CT scan showed Hoshi’s plate was placed properly and had conformed well to her remaining jawbone.
Six months after the surgery, Katy and Hoshi made the 15-hour drive back to UC Davis for a recheck examination. Her CT scan showed bone regrowth throughout the entire front arch of the jaw.