I would like a direct yes or no, can the posterior tibial tendon heal itself from tendonitis? will it always end up as pttd or can it be healed?

Yes: Yes, posterior tibial tendon dysfunction from tendonitis can be healed. However, not all patients are this lucky. Rest, ice, NSAIDs, physical therapy, and exercises are all employed to fix the problem. However, it depends how long you have had the problem and whether a flatfoot deformity exists. See an orthopaedic surgeon. http://orthoinfo.aaos.org/topic.cfm?topic=a00166

Yes: Certainly an inflammatory process involving a tendon, including the posterior tibial tendon, can and often does "heal" itself. If that were not the case, then anyone who ever had any degree of tendonitis anywhere would need surgery; and that certainly is not the case. For a variety of reasons, some patients will have a persistent tendonitis and this may ultimately need more aggressive management