Looks way more solid now, good work!
I did some minor color tweaks, I usually default to blues for teeth since it contrasts well with skintones (way better than white does) and you had blues already involved in the picture.
I also tweaked the neck shading and head shape some so the jaw made more sense!
However, I'd say these are more lateral changes than improvements, and are more meant to give you some ideas! Excelllent work.