Mouth grills are so last year. The newest (and some say safer) way to display dental bling: tooth jewelry. Unlike grills -- mouthpieces that blanket the teeth like gaudily bejeweled braces -- tooth jewelry is a less ostentatious, less expensive and less intrusive way to sparkle when you smile. Monika Linau, owner of Santa Barbara, Calif.-based DecoDent, sells a range of tooth crystals and jewelry that includes crosses, aliens, Nike-swoosh lookalikes, and gems in heart and star shapes. The jewels are meant to be attached by dentists with a composite substance. "It's basically the same process as a colored tooth...