Odell Beckham Gets Sick Diamond Crosses Implanted Into Tooth

Odell Beckham is taking training camp ice baths to a whole 'nother level ... 'cause the NY Giants star just got a handful of diamonds implanted onto his tooth!!

OBJ had the procedure done a few days ago ... and it wasn't cheap -- coming in at around $5,000 -- and his dentist tells TMZ Sports it wasn't exactly easy to do, either.

"I got my ceramist to make a porcelain veneer that looked just like his tooth," New York dentist Dr. Lee Gause says.

"And then, on that porcelain veneer, I got a diamond cross made from Odell's jeweler that he actually made on a 3D rendering that I printed and sent to his shop."

Gause tells us he then locked in the jewels on Odell's canine tooth ... and they ain't removable unless Beckham returns to the dentist's chair.