I spend a lot of time on this great site and figured that I may be able to assist someone as there is not much about bears in tutorials.
I am only a beginner taxi but will show the lip slot technique that I read about on here.
Started off with a shoulder mount and built up the gum line with colored epoxy. Other rugs I did were done with natural epoxy and then I got mouth paint over spray on the teeth. It was a pain to clean up so from now on will use the flesh color epoxy sculpt.


next I added the muscle and facial details showed in both pics. As well add the lip slot lip slot runs along the bottom edge of the clay work as well right at the edge of the upper lip line. I used an 1/8 drill bit and a Dremel machine.
Then I installed the eyes and clay them in . I tried to get them close but they usually get moved when the skin is installed and worked.

After I get the clay work done I place the form in the freezer for 1/2 hr to freezer the surface of the clay. This will stop the eyes and clay from ending out where the ears butts go.
While the form freezes I mix up some bondo for the ears

I shape the ears and pack the butts with clay as it will be the last time I can get to them as this cape is not split so no sewing is required.
Next is the form is covered from the eyes back with hide paste and the cape installed

Then roll the face back and add the hide paste to the muzzle area.
Get the nose close and then work on the lips. Start in the front middle and trim off the original lips and tuck with a tucking tool Tool I seem to use is the tool that comes with the whitetail paint color kit . Some kind of a modeling tool works well for tucking though.

I added some pins as this was my first time using the lip slot method.
finish the ears and eyes
Next pic shows the lip slot after several weeks of drying.

Fill and blend the lip slot with flesh color epoxy


let dry and paint the fur line black I didn't paint the epoxy with flesh color paint as I forgot to paint the gum line. I finished up the painting and added some varnish to the gums to give the wet look.

Like I said I am a beginner taxi and have lots to learn but the basics of the open mouth bear lip slot method is posted.
Thanks.