For the teeth and gums, you need to have the upper and lower teeth (like a set of dentures) as separate polygon meshes or groups.
• Location. Teeth should be accurately placed within the mouth, such as the front of teeth matching the inside of the lip.
• Teeth and gums should be modeled as far as they will be visible, likely including the gums and reaching into the rear of the mouth.
• Teeth and gums need to be shaded.
• The lower teeth set needs to be parented to the jaw bone.
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