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November 15, 2012

Baby; the parrot who couldn’t grow up



As part of her veterinary training, Emily undertook an elective with Dr. Larry Nemetz at his specialist avian clinic in California. This was one of his cases that required a little bit of innovation…

Baby’s beak was malformed so that the bottom part (gnathotheca) was too long compared to the top part (rhinotheca) – a condition called mandibular prognathism.

At 5 months old, Baby – a bare eyed cockatoo (Cacatua sanguinea), was still being hand fed by staff at the pet store in California where he was living. He should have been weaned by this age, but due to malocclusion of his beak, was unable to eat solid food for himself. The staff at the pet store had been repeatedly trimming what should have been the occlusal surface of the lower portion of his beak (gnathotheca) as it grew overlong, but were at a loss as to what to do long term.

The pet store staff consulted Dr. Nemetz, founder and specialist avian vet at The BIRD Clinic, Orange County, CA, to see what could be done for Baby.  He explained that the usual cause of mandibular prognathism in hand reared birds like Baby is repeated abnormal pressures on the developing beak during feeding. Dr Nemetz was confident that he could permanently make Baby’s beak normal enough that he could be weaned. He planned to do this by changing the way the rhinotheca interacted with the gnathotheca using a prosthesis made from human dental composite. The idea was that the prosthesis would provide wear for the gnathotheca and by doing so, gently apply new forces to both sections of the beak, gradually changing their shape and restoring normal beak occlusion.

Immediately post-procedure, with the prosthesis in place.

Once anaesthetised, the dysfunctional tip of Baby’s rhinotheca was removed with a high speed diamond cutting wheel. Careful to avoid the neuro-vascular supply to the beak, two titanium dental posts were inserted into the horny portion of Baby’s rhinotheca. The surface of Baby’s rhinotheca was etched to improve grip and the adhesive for the prosthesis applied and cured with a UV light. The prosthetic rhinotheca was then moulded out of human denture resin sheets and carefully applied to ensure that the forces it exerted would be efficacious. Coming from a family background of human dental medicine, Dr Nemetz was confident that the composite was resilient, malleable, non-toxic and non-heat generating – perfect for the job.

The prosthesis sloughed as intended to reveal an anatomically normal and functional beak.

Baby was re-examined every 3 weeks to make sure that the prosthesis was not causing any adverse effects.  As expected, on-going wear meant that regular top-ups of composite were required to maintain the occlusal forces on the gnathotheca. Baby was able to eat solid food with the prosthesis on, but the results of the procedure could not be truly determined until the prosthesis came off. 11 weeks post-procedure, the prosthesis sloughed off naturally, as intended.  The procedure was deemed a huge success when it was evident that the beak malocclusion had reversed and Baby heartily displayed his ability to eat solid food without the aid of the prosthesis! One final visit to Dr. Nemetz saw minor re-shaping and smoothing of the beak before Baby was ‘signed off’.

6 months post-procedure, Baby is doing well and is fully weaned. He continues to sport an anatomically normal beak, maintained by typical occlusal forces. An intimate knowledge of the biomechanics of a normal psittacine beak combined with a unique application of dental composite allowed one vet to help this little bird finally grow up.

 

Thanks to Dr Nemetz and The BIRD Clinic for providing Baby’s story and photos.