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UC Davis Veterinarians Surgically Correct Dog’s Jaw

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VMTH oral surgeons repaired Zoe’s jaw, allowing her to eat solid food for the first time.

VMTH "Case of the Month" - January 2014

—4-Month-Old Mastiff Able to Eat Solid Food for First Time—

Zoe, 4-month-old female Mastiff, had a tough row to hoe from the very beginning of her life. Born the runt of a 15-pup litter, she experienced health problems at an early age. She was born with an ophthalmia neonatorum (an eye infection contracted by newborns at birth) causing blindness in her left eye, and within her first week, she had difficulty maintaining her temperature in the normal range. When she was adopted at about 10 weeks of age, her owner noticed Zoe’s inability to fully open her mouth, although she was able to eat soft food.

Zoe was brought to the Dentistry and Oral Surgery Service (DOSS) at the UC Davis Veterinary Medical Teaching Hospital (VMTH) in September of 2013 to have her jaw examined. Smaller than average Mastiffs her age, she appeared stunted, and DOSS oral surgeons were unable to open her jaw at all.

It was recommended that Zoe undergo a CT scan to get a better understanding of her jaw. This posed a problem, though, since CT scans are performed under general anesthesia, which requires a dog to be intubated. Normal intubation could not occur since Zoe’s mouth couldn’t open. DOSS oral surgeons consulted with VMTH anesthesiologists and decided to perform the CT scan under sedation, not general anesthesia.

Zoe’s CT scan revealed that the temporomandibular joint (TMJ), which is the joint between the mandible (lower jaw) and the skull, appeared normal. However, there was a bony fusion of the left maxilla (upper jaw) and the mandible at the level of her molar teeth, likely a result of an injury sustained as a puppy. Surgeons were hopeful this area of bony fusion could be separated to allow Zoe to open and close her mouth, and restore proper function of her jaw.

Given the danger this malformation was causing Zoe, and apparent discomfort, surgery was deemed the best option. Zoe’s stunted growth was most likely due to malnutrition from an inability to eat properly, so DOSS surgeons planned her surgery as soon as possible.

To help them plan for Zoe’s surgery, the DOSS collaborated with UC Davis biomedical engineers to create a 3-D print (model) of her skull, created from images taken during her CT scan. The 3-D print, an exact replica of Zoe’s skull, allowed surgeons to view the area of bony fusion from all angles before surgery, and develop a surgical plan prospectively, making Zoe’s actual surgery shorter and safer. 

Whereas Zoe’s CT scan was performed under sedation, her surgery required general anesthesia. Because Zoe’s fused jaw precluded intubation via the normal oral route, a tracheotomy was performed and a transtracheal tube was placed for delivery of the inhaled anesthetic.

The surgery was a success. DOSS surgeons removed the entire area of bony fusion, along with some impacted adult teeth and remaining deciduous (baby) teeth. Following the surgery, Zoe could open her jaw about five centimeters. She spent the next few weeks exercising her atrophied jaw muscles by chewing on toys covered with peanut butter and cheese. At Zoe’s one-month re-check appointment, she was able to open her mouth almost nine centimeters, and continues to improve.

About the Veterinary Medical Teaching Hospital
The William R. Pritchard Veterinary Medical Teaching Hospital at the University of California, Davis—a unit of the School of Veterinary Medicine—provides state-of-the-art clinical care while serving as the primary clinical teaching experience for DVM students and post graduate veterinarian residents. The VMTH treats more than 45,000 animals a year, ranging from cats and dogs to horses, cows and exotic species. To learn more about the VMTH, please go to Timely news updates can be received on its Facebook ( and Twitter ( pages.

Rob Warren
VMTH Communications & Marketing Officer