Postural Alignment: Chan’s Dental Model – Descending vs. Ascending Patterns and Proprioceptive Signalling

By Clayton A. Chan, D.D.S.

Postural body alignment and balance are a significant aspect of optimal occlusal balance.

Mandibular position along with the associated entities of the temporomandibular joints, all the muscles of the masticatory system (including the muscles of the cervical and shoulder regions) have an effect on the lower back, pelvis, legs and feet.

Unstable pelvis is an important and significant concern, so we pay attention to those mal alignment as well. We correlate these issues to the occlusion as to how the functional disabling occlusal premature contacting surfaces intra orally can contribute negatively to other parts of the body in a descending downward pattern causing an abnormal anterior rotation of the pelvis resulting in an inward roll of the feet from supination (normal foot alignment) to an abnormal foot alignment (pronation or flat feet).

Chan’s Dental Model: DESCENDING

chans-dental-model

This is the Chan Dental Model as has been recognized and acknowledged by Dr. Brian Rathbart (professor and renowned podiatrist) while working with Chan during the years 2010-2013.: http://rothbartsfoot.es/Chans_Dental_Model.html

Proprioceptive Signalling – Where is it coming from?

The pattern of responses initially depends on whether the primary pain stimulus arises in the craniomandibular system (descending – CMD) or elsewhere (ascending – CMD).

In descending patterns of CMD the head tilts towards the site of the trauma by lateral flexion and rotation respectfully at the C1 (atlanto occipital) and C2 (atlanto-axial) joints of the upper cervical spine. Horizontal reflexes try to correct the visual tilt and occlusal planes by compensating contractions of ipsilateral lower neck, shoulder and contralateral upper back and ipsilateral lower back muscles, as well as those of the pelvis and leg muscles.

In brief, descending patterns arise from the stomatognathic or craniomandibular nocicpetion where there is an observed divergance between the occlusl, pectoral, and pelvic planes with tendency toward a double scoliosis of the cervical and thoracic- lumbar spines.

In ascending patterns, the tilt of the axial skeleton follows the nociceptively upward flexed pelvis on the ipsilateral compensating contractions of the contralateral shoulder and neck which will attempt to horizontally correct the visual and hence the occlusal plane relative to the horizon.

Chronic flexion of the cranium and mandible to the contralateral side leads to an opposite or diverging orientation pattern that characterizes the ascending reflex pattern (the stimulus originating in the foot). The compression of the jaw joint and occlusal prematurity on the contralateral side are accompanied by subluxation of the ipsilateral joint and disclusion of the dentition. Single cervical scoliosis will develop with associated joint compression, subluxation, and associated pain. What we then see in chronic pain is a progressive painful postural stiffening and resultant abnormal postural pattern.

Wearing Foot Orthotics and Mouth Orthotics
I personally believe from my experience that treating the mouth and jaw issues will dominate foot issues over time due to the power of the trigeminal neural sensory feedback loop. If the chronic TMD patient is wearing a foot orthotic in conjunction with an “optimized GNM orthotic” (well adjusted to physiologic parameters) my patient’s over time end up eliminating their foot orthotics. As the mandible becomes physiologically aligned to the cranium in a healthy manner the cervical bones as well as lower back and pelvis also begin to positively respond by correcting the abnormal anterior pelvis rotation. If the tibias of the knees are turned inward (pathologic) they will then begin to align resulting in flat pronated feet to move toward supinated normalized feet alignment. That is how a healthy aligned dental occlusal relationship can positively effect and improve over all body alignment.

If one is wearing a splint or orthotic in the mouth at the same as a foot orthotic the proprioceptive signally between the two will be trapped between the feet and mouth within the body (competing descending and ascending signals) …depending on how the mouth orthotic is adjusted and positioning the jaw…..not good. Either the mouth/occlusal signaling or the food signaling will try to over power the other. Foot signals (ascending) will not correct mouth/teeth (dental) signalling. I know most folks and doctors may not fully grasp and understand this sentence and concept.

The trigeminal nerve system (V) is a very powerful entity to over all body posture and alignment.

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