11:30 AM PT -- Tiger's agent Mark Steinberg says the tooth was knocked out at the skiing event ... claiming a photog accidentally smacked the golfer in the face with a camera after the race.
"During a crush of photographers at the awards podium at the World Cup event in Italy, a media member with a shoulder-mounted video camera pushed and surged toward the stage, turned and hit Tiger Woods in the mouth."
He adds, "Woods' tooth was knocked out by the incident."
Hole in one ... mouth.
Tiger Woods proved the old adage ... old wounds never heal ... when he flashed a toothless grin after his GF Lindsey Vonn won a World Cup alpine skiing race in Italy this weekend.
Tiger was undercover at the race ... courtesy of a mask featuring a skull ... which had a full set of chompers.
But when he moved in to kiss the victorious Lindsey, the mask went down and Tiger showed what appeared to be the remnants of what became one of the most famous domestic disputes ever.
So, how'd he lose the tooth? Rewind to that Thanksgiving night when Elin Nordegren reportedly threw a phone at him, destroying at least one of his pearly whites.