Rio de Janeiro: Brazilian authorities seeking to take a bite out of crime caught a lucky break when a purse-snatcher unwittingly left behind key evidence that led to the thief's arrest: his own dentures.

The robber grabbed a woman's handbag in the small town of Severina, about 430km from Sao Paulo, and managed to escape, victim Silvina Julieta Ferreira told local media on Friday.

The news quickly spread within the community, and the thief would have remained at large had it not been for an alert farmer who found the dentures and turned them in to police.

Investigators promptly showed up at the home of 34-year-old Milton Cesar de Jesus, who was missing most of his front teeth.

"He was told to put on the dentures and they fit perfectly. You couldn't say they weren't his," town commissioner Aparecido Martins said.

The accused was left without his false teeth once again, television stations showed on Friday, as police had taken the dentures into custody as evidence.