Once I had access to the mouth I began building up the gums and interior of the mouth using Apoxie Sculpt clay. This is a two part modeling material that is mixed in equal amounts by hand. It sets in a few hours by chemical reaction.
When I was satisfied with the gums I marked off the locations where I wanted the teeth to go. Next I took the tongue that I had sculpted the evening before and set it into the wet clay. One of the benefits of using Apoxie Sculpt is that it acts like an adhesive and will bond strongly to most materials.
I made a slight depression for each tooth and sunk them into the gums. Using a stiff brush and some water I smoothed the gum area around the teeth and the tongue. After the Apoxie Sculpt set up I painted a base coat of acrylic pinkish flesh on the gums and tongue. Here are a couple photos of Kong with his new choppers.