I work with clients who can act out. They hit things, shout and sometimes even throw chairs at me (mental health clients and criminal defense clients). I have never really been afraid of a client - even those who were trying to be intimidating. I was once threatened by a client's family and that was a bit unsettling, but I still represented the guy.
I just think one needs to butch up a bit if one is going to be a therapist (or attorney), or as another poster said - work for only those with dental phobias. Frankly the description from the OP just did not sound like a big deal to me - not particularly violent or threatening at all.