Dogs missing part of their jaw because of an injury or disease someday may grow a new one through procedures being perfected at the University of California, Davis, School of Veterinary Medicine. Two veterinary oral surgeons — Frank Verstraete and Boaz Arzi — have successfully reconstructed most of the lower jawbone in three dogs over the past year using refined techniques, the university reported. Among the beneficiaries was Hoshi, a 10-year-old female collie who went to a Montana veterinarian last summer because of swelling in her mouth and extremely bad breath. The veterinarian diagnosed a type of cancer called squamous cell carcinoma and removed diseased bone and tissue from the front of Hoshi's mouth. UC Davis School of Veterinary Medicine A CT image of Hoshi’s skull shows the titanium plate used to form her new jawbone, along with the new bone growth behind the plate. Wanting to do more for Hoshi, owner Katy Harjes took her to UC Davis, where she was examined by Drs. Verstraete and Arzi. The veterinarians had already begun working with UC Davis biomedical engineers to regrow segments of canine jawbone lost to injury or tumors such as squamous cell carcinoma. The procedures they developed involved removing loose bone fragments or a jawbone section, attaching a titanium plate in the missing area and inserting a sponge-like material soaked in bone morphogenetic protein. The growth-promoting protein stimulates the remaining jawbone to grow new bone cells, eventually extending the bone, the university stated. Bone growth can be detected in as little as two weeks, and most of the targeted area is filled with new bone within four to six weeks. A continuous mandible develops by weeks 8 to 10. "Once they told us about the surgery, we were on board immediately knowing the success rate," Harjes said. "It seemed too good to be true, so of course we were very excited and grateful for the opportunity." Hoshi's treatment required removal of the lower jawbone along both sides of her mouth to erase all of the diseased tissue and the use of 3-D modeling and printing of her skull to help plan the other steps. The 3-D print helped Verstraete and Arzi design the titanium plate and shorten the time necessary for surgery and anesthesia, UC Davis stated. Now a walking and barking success story, Hoshi is back on her Belgrade, Mont., sheep ranch. The only problem with her shortened lower jaw is it hampers her ability to eat and pick up toys, and she has had to make adjustments because of fewer nerve endings in the front of her mouth. One allowance Harjes made was to elevate Hoshi's food, placing it on a bench to line up better with the collie's mouth.
