tin grin

tin grin

slang The mouth of someone who has dental braces. Also used as a mocking nickname. I never used to smile for photos when I was in middle school because I hated the way my tin grin looked. Nice smile, tin grin! Don't get too close to any magnets, or you'll get stuck!
See also: grin, tin
Farlex Dictionary of Idioms.

tin grin

n. a smile with a mouth having braces. I’ll be glad when I get rid of this tin grin.
See also: grin, tin
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • be (flat) on (one's) back
  • come in
  • come in a certain position
  • come on in
  • damn well
  • flat on (one's) back
  • flat on back
  • (Is) this taken?
  • DYODW
  • (Is) that everything?
References in periodicals archive
Its two new animated series are already generating interest from buyers: "Braceface," a co-production with China's Jade Animation, featuring Alicia Silverstone as a `tween girl with a tin grin, and "Cyberchase," a TV-Web hybrid about a group of kids summoned into cyberspace.
ACTION PACKED
While this method was effective, it created the "tin grin" look that many patients found unappealing.
Moving teeth with technology
"You'll see for yourself soon." Ng Lok Tin grins mysteriously.
The Reunion