Occlusion Connections — The Center for Gneuromuscular Dentistry & Orthopedic Advancement

Centric Relation Isn’t Outdated — But It Is Incomplete

Doctor EducationWhat CR Does Well — And Where It Stops

Centric relation has served dentistry well for decades. The structural logic is sound. The repeatability argument is legitimate. The condylar seating philosophy has produced excellent outcomes in thousands of cases.

The gnathologic tradition — from Stallard and Stuart through McCollum, and carried forward by dedicated clinical educators including Peter Dawson, whose gnathologic framework remains one of the most influential in the profession, and John Kois, whose evidence based approach to restorative occlusion and risk assessment has shaped a generation of clinicians — represents some of the most rigorous thinking dentistry has produced. These are serious clinicians and serious scholars. Their commitment to elevating the standard of clinical dentistry is something this author shares and respects deeply.

The question this page raises is not whether their work is wrong.

The question is whether it is complete.

The Repeatability Argument — And Its Limit

The strongest case for centric relation is repeatability. A manipulated condylar position — whether achieved through bimanual manipulation, a Lucia jig or a leaf gauge — can be reproduced visit to visit. That reproducibility is clinically valuable. It gives the dentist a reference point.

But repeatability is not the same as physiologic acceptance.

A position can be perfectly reproducible and still not be the position the masticatory system prefers. The condyles can be seated in the most superior anterior position in the fossa — as the classic CR definition requires — and the musculature can still be in a state of compensation rather than rest.

Centric relation may be repeatable — but that does not mean it is physiologically accepted.

This distinction is not semantic. It is the difference between a reference point the clinician can reproduce and a reference point the neuromuscular system has accepted as stable.

What CR Cannot Measure

Centric relation as a clinical concept addresses condylar position. It does not address:

  • Whether the masticatory muscles are in a genuinely relaxed state at that position
  • Whether the mandibular trajectory closing into that position is the optimized neuromuscular path
  • Whether the cervical musculature — which is neurologically linked to the masticatory system through the trigeminal-cervical convergence pathway — has accepted that position as stable
  • Whether the occlusal vertical dimension established at CR corresponds to the physiologic vertical dimension the neuromuscular system requires
  • Whether EMG activity in the masticatory and cervical muscles is symmetric and within physiologic range at that position

These are not peripheral considerations. They are central determinants of whether a treatment outcome will be stable long term.

The articulator mounted in CR shows what the teeth do at that position. It does not show what the muscles are doing. And in the complex TMD patient the muscles are frequently the primary driver of instability — not the condylar position.

The GPT-9 Signal — What the Profession’s Own Definition Reveals

In May 2017 the American Academy of Fixed Prosthodontics published GPT-9 — the ninth edition of the Glossary of Prosthodontic Terms. The updated definition of centric relation included two words that had never appeared in any previous edition:

Physiologic. Unstrained.

For the first time in the history of the GPT definition centric relation was described not merely as a border position or a condylar relationship — but as a position that must be physiologic and unstrained.

This is significant. The profession’s own authoritative reference had quietly moved toward the language of neuromuscular science. The word retruded — which had defined CR from GPT-1 through GPT-4 — was fully abandoned. The condylar position was no longer defined by its posterior limit but by its physiologic acceptability.

GNM had been making this argument for decades before GPT-9 validated it.

The question GPT-9 raises but does not answer is: how do you verify that a position is physiologic and unstrained without objective measurement?

Bimanual manipulation cannot answer that question. A Lucia jig cannot answer that question. Articulating paper cannot answer that question.

Only objective measurement of muscle activity — EMG — combined with jaw tracking and electrosonographic joint analysis can answer that question.

Where GNM Completes What CR Begins

GNM does not reject the condylar seating philosophy of CR. It extends it.

The gnathologic insight — that condylar position matters, that the disc-condyle relationship is clinically significant, that structural integrity of the TMJ is foundational to occlusal stability — is preserved and integrated into the GNM framework.

What GNM adds is the measurement layer that CR has always lacked:

  • J5 Dental TENS to achieve genuine physiologic muscle rest — not manipulated rest but neurologically confirmed rest
  • K7 jaw tracking to record the optimized myo-trajectory in all six dimensions — the path the mandible follows when the musculature is truly relaxed
  • Surface EMG to confirm bilateral muscle balance before and after treatment
  • Electrosonography (ESG) to evaluate joint sounds and condylar behavior during function

When these measurements are taken the position the mandible finds is often close to — but measurably different from — the manipulated CR position. That difference — sometimes less than a millimeter — is the difference between a case that holds and a case that keeps coming back.

The Clinical Question That Changes Everything

Every dentist trained in CR has asked some version of this question:

I did everything correctly. Why isn’t this case holding?

The answer in most of these cases is not technique failure. It is a measurement gap. The position was established correctly by CR standards — but CR standards do not include a method for verifying whether the neuromuscular system has accepted that position as stable.

GNM provides that method.

The shift from CR-based occlusion to GNM-based occlusion is not a rejection of everything a dentist has learned. It is the addition of an objective measurement layer that finally answers the question CR has always left open:

How do you know the system accepts this position?

Frequently Asked Questions

🔹 Is centric relation wrong? No — and that is precisely the point of this page. Centric relation has served dentistry well for decades. The structural logic is sound. The repeatability argument is legitimate. The condylar seating philosophy has produced excellent outcomes in thousands of cases. The gnathologic tradition — from Stallard and Stuart through McCollum, and carried forward by dedicated clinical educators — represents some of the most rigorous thinking dentistry has produced. The question is not whether CR is wrong. The question is whether it is complete. And on that question — verified against objective measurement of the masticatory and cervical musculature — the honest answer is no, not yet.

🔹 What is the difference between repeatability and physiologic acceptance? The strongest case for centric relation is repeatability. A manipulated condylar position — whether achieved through bimanual manipulation, a Lucia jig or a leaf gauge — can be reproduced visit to visit. That reproducibility is clinically valuable. But repeatability is not the same as physiologic acceptance. A position can be perfectly reproducible and still not be the position the masticatory system prefers. The condyles can be seated in the most superior anterior position in the fossa — exactly as the classic CR definition requires — and the musculature can still be in a state of compensation rather than rest. This distinction is not semantic. It is the difference between a reference point the clinician can reproduce and a reference point the neuromuscular system has accepted as stable.

🔹 What clinical factors does CR not measure? Centric relation as a clinical concept addresses condylar position. It does not address whether the masticatory muscles are in a genuinely relaxed state at that position. It does not address whether the mandibular trajectory closing into that position is the optimized neuromuscular path. It does not address whether the cervical musculature — neurologically linked to the masticatory system through the trigeminal-cervical convergence pathway — has accepted that position as stable. It does not address whether the occlusal vertical dimension established at CR corresponds to the physiologic vertical dimension. It does not address whether EMG activity in the masticatory and cervical muscles is symmetric and within physiologic range. The articulator mounted in CR shows what the teeth do at that position. It does not show what the muscles are doing. And in the complex TMD patient the muscles are frequently the primary driver of instability — not the condylar position.

🔹 How does GNM complete what CR begins? GNM does not reject the condylar seating philosophy of CR. It extends it. The gnathologic insight — that condylar position matters, that the disc-condyle relationship is clinically significant, that structural integrity of the TMJ is foundational to occlusal stability — is preserved and integrated into the GNM framework. What GNM adds is the measurement layer CR has always lacked: J5 Dental TENS to achieve genuine physiologic muscle rest verified neurologically rather than manipulated; K7 jaw tracking to record the optimized myo-trajectory in all six dimensions; surface EMG to confirm bilateral muscle balance before and after treatment; electrosonography (ESG) to evaluate joint sounds and condylar behavior during function. When these measurements are taken, the position the mandible finds is often close to — but measurably different from — the manipulated CR position. That difference is sometimes less than a millimeter. And it is the difference between a case that holds and a case that keeps coming back.

Continue Learning

🔹 CR vs Physiologic Occlusion

🔹 The Measurement Gap

🔹 The Original Science Behind GNM

🔹 Ready to Train

Written by Clayton A. Chan, D.D.S. — Founder and Director, Occlusion Connections | Las Vegas, Nevada

Doctor EducationDoctor Education
Patient EducationPatient Education

Share this:

Like this:

Like Loading…