Thank you for sharing your thoughts! Could you please share the name for the probiotic wafers your dog likes?You'd have to ask them re the MSG... I don't know if this could be pertinent, but my dog's breath goes off each time he eats his favorite probiotic wafers. Clears up in two days, doesn't affect his teeth - and other chews don't produce that particular odor.
I've mentioned this previously, but we like Teef! and PetLab's Probright. After a thorough cleaning, teeth are holding great six months out.