A sloth has had pioneering dental surgery to cure toothache.

Rico is believed to be the first sloth to undergo such an operation, which was carried out by a team at Chester Zoo working alongside dental experts from Newcastle University.

The two-toed sloth went under the knife after keepers noticed swellings on the sides of its face, with investigations showing two root abscesses.

Dentist Fiona Beddis said the university’s team had never carried out the procedure on a sloth so it “really was a step into the unknown, so we are all delighted with the successful outcome”.

Ms Beddis said treating Rico had been a once-in-a-lifetime opportunity and it was “a great privilege to treat such a rare and beautiful animal”.

Rico, who is 25 years old, had a three-hour operation at Chester Zoo’s animal care centre, with the infected tissue surrounding two of the sloth’s teeth removed.

Unlike a typical root canal, the dental experts went in through the bottom of Rico’s tooth.

Dave Edwards from Newcastle University’s School of Dental Sciences said the surgery involved removing the end of the tooth root and “sealing it with special cement”.

He said it was “very challenging working on a sloth due to their unique anatomy, but also a very rewarding experience”.

Resident zoo vet Charlotte Bentley said the teeth that they operated on were “highly specialised and sharp molars”.

She said sloths had “very different teeth to humans, which makes dentistry challenging”.

“Whilst we couldn’t save both teeth, the great news is that since his procedure, the abscesses have not come back, and his latest X-ray shows his filling is still in place,” she added.

“It’s safe to say that the treatment worked at treating his toothache.”

Rico, who lives with Tina, a female two-toed sloth, in the zoo’s jaguar house, has been regularly monitored since the surgery.

Rico’s keeper, Brittany Williams, said “it could be slow progress calling Rico for health checks following the surgery as “he goes at his own pace”, but she added: “I don’t mind working at sloth speed.”

Two-toed sloths are found across South America, where they face threats including habitat loss, logging and hunting for the illegal wildlife trade.

Chester Zoo is part of a conservation breeding programme working to safeguard the species across Europe.