Look how old some of those shots of her smiling are !!! I don't think she's been caught smiling and showing her teeth since Romeo was a babe in arms !
Notice the very latest 'huge broad grin on the catwalk' wasn't caught at all, as she immediately clamped both hands over her mouth. She does this ALL the time. I even read an article recently where Cheryl Cole mentioned that when they were WAGS together at the World Cup (?) that she noticed Victoria laughed but 'immediately put a hand over her mouth'. Cheryl thought it was strange, insecure behaviour and it is.