Hamilton Zoo's Sumatran Tiger Jaka has had a surgical root canal.
Keepers noticed during regular checks that 13-year-old Jaka had chipped off part of his lower left canine tooth, exposing the root canal.
Hamilton Zoo Veterinarian Mike Goold says surgery was absolutely necessary.
If left untended, the tooth would have been at high risk of infection and an abscess may have developed, he says.
"A Sumatran tiger's canine tooth is about 18cm long and two-thirds of it is embedded in the lower jawbone. If an abscess developed in a tooth of this depth and strength, the surgery would need to be much more invasive".
The root canal procedure involved drilling two holes in the 60mm wide crown of the tooth, to allow for any dead material to be flushed away.
During the procedure x-rays were taken to ensure the instruments had reached all the way down the tooth and to check that surrounding bone and tissues were healthy.
Finally, the tooth was filled with materials that set with UV light, just as in human dentistry.
Mr Goold says the operation went well and Jaka has made a full recovery.
"As the nerve in the tooth is dead, there was no pain associated with the procedure and Jaka had no discomfort once he recovered."
Veterinary dental specialist Dr Russell Tucker, from Auckland, performed the root canal work, generously donating his time.
He has performed other dental work at Hamilton Zoo, on the African wild dogs and chimpanzees.