in a way that people can understand better. May be you need to understand what TMJ and TMD are (and then talk to your doctors one more time?) so that your question is a little more specific? "tmjd causes a forward shift in the tmj" -- I'm not sure of this.
Also, what is your goal? Pain relief? maybea mouthguard with botox and physical therapy If it's just cosmetic, be aware that moving a jaw forward is a horrendous abount of surgery and recovery time -- maybe you can do it another way with like above or veneers.
Maybe you should read all the tmj tips sticky