What you have produced, it was exactly that: 1. you draw a rectangular teeth, but actually as curved teeth it must end. You see notice 2 smearing colors. Mouth, tongue, teeth, it's not slick.
What you made it wrong that 1 tooth you draw a rectangular shape, but actually it's teeth have curved edges. See Notice 2 color for the lips, teeth, tongue is not smooth.
What you produce very wrong. That 1. You draw a rectangular teeth tooth model it must bend but at the end, you look 2. The colors used in the application. Mouth, teeth, tongue, it is not smooth.