This was an interesting project. Instead of the recommended 5.5 mm I used dpns of a smaller size (4 mm) because I didn’t have anything larger, so I’ve always added a few stitches here and there. Later it turned out into 120 stitches where it should’ve been 80 and the hat was huge. I had to frog it all the way back to 30 stitches and start all over again.
I also tried using circular needles at one point but I had problems with the stitches getting stuck for some reason, so I went back to dpns after a few rows.

After finishing the “gums” I found out the hat was too small even though the number of stitches was right. The problem was actually in the bind off: I used the classical bind off and the result was not at all elastic.

I found on Youtube this great video about how to do 2x2 invisible ribbing bind off which first of all looks much better and second it’s very elastic. This technique is complicated but you can get into it very quickly and it really pays off to learn it.

For the teeth I used smaller needles because I only had sport weight yarn.