I suspect because it tastes horrible. Before I had all my extractions and implants done I basically had constant abscesses and toothaches. One was so bad that I pulled my own tooth because it was Saturday afternoon. That's major pain, when you yank out your own tooth and its BETTER.
I used a lot of clove oil packing. If it gets on your tongue its so nasty that it used to make me throw up. It worked really really well but its just horrible stuff.