in my opinion this is rather typical of Aspies. When Wiz was first in preschool there was a boy a year older who was clearly an undx'd Aspie with a dental fixation. This boy pulled out 6 of his own teeth in a 5 week period and then proceeded to start pulling other kids' teeth. We learned about it when we got a very upset call from the school - Wiz had just spent a weekend in tears because he wanted the slightly loose tooth OUT and then he didn't want anyone to mess with it or touch it and wanted it to stay IN and was crying because he thought we were going to pull it, back and forth all weekend. Then the boy at preschool, J, learned he had a loose tooth. J cornered Wiz and yanked it out (it was quite loose after the off and on, or rather in and out, weekend).
While neither husband or I was upset with J in the least, largely because we figured Wiz had either asked him to pull it or because Wiz went into his pull it out, no leave it in, no pull it out, cycles. J's mother was, of course, horrified and offered to pay for the dentist, etc... From all we could see it looked just fine, no infection, etc...
If it helps at all, I saw J's facebook a week ago and he is now in dental school. He did a special high school program and graduated early, now is doing a combined bachelors/dental school program somewhere. He didn't remember pulling the teeth except his own, but between one of my cousin's and I, we reminded him of 4 little boys he played 'dentist' with that year.
For Wee I would say that there is something sensory going on. The Occupational Therapist (OT) needs to work with him to help find other ways to fill his need. As Wee may need help a lot faster than the school may respond, check out both The Out of Sync Child Has Fun for ideas. I know they have some sort of vibrating thing that can have various ends put on it to give oral stimulation. You might try one of those ten dollar electric toothbrushes instead.
If he needs a flavor maybe sugar free syrup like they put in coffee could help. I would normall suggest chocolate syrup, but this will likely spend substantial time in his mouth, so the sugar free ones might be best. Before you buy a bottle, ask at starbucks or a local coffee shop if you can buy a shot of the syrup in a cup. Or take your own container with a lid, maybe a small gladware type container, and get a shot of each sugar free flavor so he can try them. Then let him put a bit of the syrup on the brush and put it in his mouth. If he doesn't like the bristles, maybe they can be trimmed so they won't bug him? It is just a thought.