As indicated above, there are two kinds of teeth, tusk type ones and ordinary ones. Ogres and Gorlaks have tusk type teeth, and I'm fairly sure they can be knocked out in combat, as I have had problems with those in the past, and I'd expect it can happen with an elephant, walrus, etc. as well (0.40.24 experience, though). Since I don't think sapient parts can be processed in 0.42.03 (they could in 0.40.24, if the butchering happened "naturally" and they weren't dwarves), there is no longer any use for these sapient large teeth.
Smaller teeth used to go into the body part refuse stockpile category, but since sapients now end up in the corpse stockpile, I think their teeth go there as well, and would expect tusks to do too. ...Just checked my fortress, and goblin teeth have been hauled to the corpse stockpile. I don't have any sapient's tusks to check, though.
Thus, Bouchart is slightly out of date. If it's sent to either the corpse or the refuse body part stockpiles it's useless, if it's sent to the teeth/ivory one it can be used, but I don't make that refuse distinction: just send all refuse to the refuse pile and sapient corpses to the corpse stockpile. When starting my bone carving jobs I just set ivory, horn, and totem on repeat, together with whatever bone ones I want. Various pieces of rings etc. are produced, but I haven't paid much attention to what animals they came from, as in the past, it was just a way of getting rid of garbage (via the caravan garbage removal service). Given that there seem to be some ivory jobs, I'd expect large haulers (horses, etc) to yield ivory type teeth.