Dr. Jason Auerbach Reveals What Work Jack Hughes Needs After Tooth Knocked Out

Ice hockey star Jack Hughes turned the ice red before he turned it gold -- flashing a blood-soaked, tooth-jacked grin after burying Team USA’s crowning goal ... but one top doc says that smile might need a whole lot more than a victory lap to recover!

Dr. Jason Auerbach -- board-certified oral and maxillofacial surgeon for the New Jersey Devils -- broke it down for us on "TMZ Live" Monday, telling us the 24-year-old looks like he fractured his left front tooth, possibly shoved another out of place, and may have even rattled his upper jaw. Ouch.

Watch the clip -- the doc goes full dental dictionary on us, spelling out how Hughes is probably staring down serious restorative work, starting with a quick temporary fix while swelling peaks in the first 48 hours.

As for the full smile comeback? Could take weeks -- longer if surgery's in play. For the full bite-by-bite breakdown, hear it straight from Dr. Auerbach.

Meanwhile, Jack shrugged the injury off to reporters Monday ... saying in hockey, losing a tooth happens. He did acknowledge he was disappointed when he felt a tooth was missing, but no panic here. He says he’ll get it fixed -- because that gold-medal grin is coming back.

ICYMI -- Hughes took a stick to the mouth from Sam Bennett in the third period of the men’s hockey final at the Milan Cortina Games on Sunday ... then casually went on to score the gold-medal goal. Talk about biting back!