Sofia Richie Grilled Over Bieber Breakup And Feeling Golden

Sofia Richie is going for the gold after splitting with Justin Bieber ... ordering up 3 custom grillz.

New York jeweler Richie Nektalov, aka Richie Rich, tells us he stopped by Sofia's pad while he was in L.A. last week to personally fit her for the grillz.

We're told Sofia went all 14 carat gold and high quality diamonds ... which cost between $2,500 and $3,000 each.

Best way to get over a breakup? Spend about $9k to brighten up your smile.