Is the model wearing contacts? There is something about her eyes, and by extension her face, that gives the appearance that she is like a deer in headlights, or she is uncomfortable.
If she wears glasses normally, have her try them - it might go well with the braces.
She has nice boobies and is generally good looking, but the poses look unnatural and unimaginative (boring).
I'm sure she will sell, but if you make some changes - add more contrast to the scene (a pale white girl with blownout lighting against a white couch and drapes is tough to pull off), put in a prop of some kind to give her something to focus on, tell her to relax her shoulders, and I think you will be able to market her more.
ADG