What is the significance of this quote from The Great Gatsby?

The man wearing them is a mobster. There's another quote where it's said he was one of the men who helped fix the 1919 World Series (the one where Shoeless Joe Jackson and the Chicago White Sox took a dive and lost). The molars are probably from someone who crossed him or owed him money. And back then novocaine was probably not widely used, or any other painkiller, in dentists offices. And DEFINITELY not used by mobsters with steel pliers.