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 into his teeth!!
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 ceramus 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.