Following the 0-0 stalemate at the rain-soaked Amex stadium, the Brazilian was spotted searching for one of his gnashers on the pitch after he lost it in during a collision during the game.
The Gunners defender collided with Brighton goalkeeper Robert Sanchez in the second half of the clash, which the Seagulls dominated and were unfortunate to claim all three points.
Incredibly, Gabriel has lost his tooth during a game before - and against Brighton of all teams.
Last season, the former Lille man lost his tooth against Graham Potter's men at the Emirates, as revealed by a sports journalist on Twitter.
Albion edged a rain-soaked encounter on the south coast but managed just two attempts on target as Leandro Trossard, Dan Burn and Neal Maupay each failed to capitalise on decent openings.
Pierre-Emerick Aubameyang headed against the outside of a post for the uninspiring Gunners, who were denied a fourth victory on the bounce having begun the campaign with three successive defeats.
The Seagulls sit fifth with 14 points from seven games, with Mikel Arteta's visitors four places and as many points further back.