Detectives plan to publish photographs of a dead man's teeth in a bid to discover his identity.
They hope dentists will recognise the distinctive gold tooth and bridgework and help solve the mystery.
The man's dismembered body was washed up on Hove beach. The legs were recently washed ashore opposite Brunswick Square.
Later the same day, his torso and head were spotted out at sea and recovered by a lifeboat crew. A foot was found on the beach near Brunswick Square. The other is still missing.
As the man's hands are still missing, fingerprints cannot be checked.
Officers hope the DNA database in Birmingham will produce a match but if that fails, the man's teeth could assist.
Detective Inspector Bill Warner, of Brighton and Hove CID, said he may take the step of publishing a photograph of the man's jaw and teeth in a dental journal in the hope the dentist who carried out the work will come forward with a name.
As officers do not know the man's identity, they are unable to check dental records, a procedure often used to identify bodies.
Mr Warner said the baffling case was one of the most unpleasant officers had dealt with. He said foul play was not suspected.
He said: "It appears the body had been in the Channel for up to three months and had decomposed to the point that parts broke off.
"It is difficult to speculate where he entered the sea and our checks with missing persons lists have proved fruitless.
"I spoke to the British Dental Association and they said this is an extremely rare step but it has been done before.
"This is a tragic death and, no matter what the circumstances, the object of our inquiry is to inform his next of kin."
Mr Warner said there were no distinguishing marks on the body and his clothing had been torn off by the sea. All that was left was a pair of Influx underpants.
The man may have fallen overboard from a vessel miles off shore. He was aged 40 to 50, 5ft 8in to 6ft tall, with dark brown hair.
The mystery comes as detectives still try to identify a man whose body was found on the same day at the Middle Terrace, Madeira Drive, Brighton.
An empty bottle of vodka lay by his side and a post-mortem examination revealed he died of alcohol poisoning.
He had a faded tattoo on his left forearm, showing the figure 02.
Anyone with information on either case should call Mr Warner on 0845 6070999.
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