(adj.) Old, outdated. no longer to perform its primary function at optimum level.
The playstation one is a bit long in the tooth these days.
by Kung-Fu Jesus June 07, 2004
old, advanced in age(from the practice of judging a horse's age by the length of it's teeth)
The plumbing is a bit long in the tooth. It needs to be replaced.
by The Return of Light Joker January 21, 2010