The Roncone PhysioDynamicSystem (PDS)

I have for many years said that “If you do not know how and why muscles work, you cannot be a superb orthodontist.” I have been unable to comprehend the AAO position that occlusion (teeth) and condylar position are not related. Look at the anatomy of skull (fossa), mandible, ligaments, muscles and teeth. How can they all not be related?figure1-anatomy-of-the-skull

The neuromuscular response is king! One cannot with impunity “override” the muscles either by heavy-handed manipulation to an exact point or “pulling” them to a location (any location) to allow the overjet to be reduced. There is a relaxed, appropriate resting length to each muscle. This position must be achieved in order to:

  • Know where we are > At the start of treatment
  • Know where we are > During the treatment process
  • Know where we are > At the end of treatment

Centric relation to me occurs when I can gently hinge the mandible without muscle splinting. This can only occur when muscles, individually and as a group, are relaxed. They must be relaxed in order to know where centric is and therefore what the occlusion is.

Bracket prescription, bracket position, correct wire sequencing etc., etc. are useless, unless we first get the muscles under control (relaxed).

The Roncone PhysioDynamic System consists of 6 specific steps which are followed sequentially:

  1. Achieving full muscle relaxation of head, neck, and face. This is absolutely essential. It is not in any way related to the use of pulse machines or electromyography. It is relatively simple to achieve.
  2. Superb diagnosis using a checklist method and attention to the “Diagnostic Dozen”.
  3. The PDS Prescription using self-ligating brackets for maximum efficiency only.
  4. Precise bracket placement.
  5. Two to three distinct stages of treatment. Knowing when you are finished greatly reduces relapse.
  6. Post-removal finishing for function and aesthetics.


Orthodontists have a significant medical/dental responsibility. We are responsible for slow, full-mouth reconstruction and very slow, facial orthopedics and soft tissue changes. What we do (orthodontics) must be based on some very basic tenets or principles:

  • Sound physiological/anatomical considerations
  • An understanding of the musculoskeletal system
  • A thorough understanding of biomechanics
  • A re-education on the role of friction in physiological tooth movement
  • The functional coordination of:
    1. Joint position
    2. A relaxed, posturally correct muscle system
    3. An occlusal scheme which is non-traumatic
    4. The best facial aesthetics genetically possible
  • Minimal reliance on patient cooperation


Experience the results of the PhysioDynamic System.

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