The singer's got some shiny new gold grills -- 24 karat gold covering all 28 teeth according to his celeb dentist Thomas Connelly -- but that's not what makes 'em special.

Connelly says it's the magnetic retention design, where Breezy's back molars have magnetic gold crowns embedded on them so the grills fit and lock in the magnets with precision on the fronts of all his teeth.

This means CB's grills have no metal covering the inside of his teeth -- like conventional grills -- so he can basically speak and sing normally while wearing them.

Obviously, dental work this revolutionary doesn't come cheap, and we're told the cost for Brown's job was just under $100,000.