The Molar Lever

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What is the relationship between teeth and body posture? How does dental occlusion affect the allignement of the spine? The shortest answer has two words: Molar Lever.

The mechanism by which the skull is supported by the dental arches and influences and controls the allignement and elevation of the cervical spine is difficult to make out because the support is only momentary during dental contact.

This mechanism is based on the Molar Lever, a bio-mechanical type 1 lever that finds its fulcrum on the molar teeth.

Don’t worry if you find it difficult to envision this mechanism and relation. Many dentists or orthodontist do not know or understand this mechanism either, as it is not part of most modern accademic  curricula.

With the following picture you can get a rough idea of what we mean by Molar Lever that lifts the skull.

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After you have read this post and looked at the evidence, description and  images that we present, you will probably understand it and see it as self-evident.

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You will probably be as amazed (or appalled) as we are by the fact that dentists and men of science who dedicate their life to dental medicine and the masticatory science do not see what is evident, beneath their eyes.

As a matter of fact, we are including in  this post pictures of an orthopedic appliance built and regularly used by an orthodontist which is based on the mechanics of the Molar Lever.

This orthodontist (who is a truly excellent dentist and orthodontist, specialized in difficult cases, including patients with Down Syndrome and Multiples Sclerosis) told us quite literally:

“I use this appliance before most orthodontic treatments because I was taught to use it and I have experienced that it works. My professor could not explain how it worked and until I was introduced to the concept of Molar Lever, I did not fully understand it either.”

The dental appliance covers and raises the vertical dimension of the posterior maxillary teeth.

It is built to allow occlusal contact only between the most posterior teeth of the mouth, the second molars.image

The Molar Lever at Work

In the next two pictures tou can se how the Molar Lever works:

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By applying force with the hand along the same direction that the masticatory muscles do (red arrows in the picture), you can clearly appreciate how – as the mouth closes – the posterior part of the mouth is subject to a stretching force (green arrows in the picture): the white plastic sustainers slide along the rails and the distance between the mandible and the maxilla in the back side of the mouth is raised about half a cm.

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That is how the lever centered along the molar part of the dental arches stretches the back of the cervical spine and lifts the skull.

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Thus, the masticatory muscles transfer their grinding force by means of a bio-mechanical lever to the cervical spine,  stretching it and elevating the skull.

Structural Allignment: the Dental Connection

It is also important to note that this whole complex bio-machanic lever is composed of elements that are all mobile: the vertebrae, mandibles and skull are all connected by joints. The only fixed element is the dental arches when they interlock.

dental occlusion

Thus, the shape, inclination and forces of the interlocking of the dental arches is the only fixed element that shapes and alligns the rest of double lever machine. The contact of the teeth – occlusion – serves to transfer the shapes to be taken on to the adjacent and underlying musculoskeletal structures.

It is evident that, if the fulcri of the Molar Lever rest on the teeth at asymmetric hights or distances, the stretching force that will reach the back of the mouth will be asymmetric or even of a rotational-twisting nature.

If the plane of dental occlusion is not alligned with the axis of the skull and cervical spine, the skull tilts and twists.

If dental support is not adequate, the skull tends to collapse. Thus the top cervical vertebrae get miss-alligned and the skull tilts and moves away from a stable, centered, symmetrical and balanced position on top of the shoulders.

In the event that the skull comes to fall, the spine undergoes changes proportional to the extent of the collapse of the skull. As a result there are musculoskeletal compensatory measures of a descending kind.

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Repairing the Broken Molar Lever

The Molar Lever is the fundamental orthopedic force that the Rectifier uses to progressively and gradually stretch and recover verticality of the spine.

The next picture shows how using a splint based in the principle of the molar lever can straighten the spine in a period of 1 year.

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Navigating this Blog

To further understand our reasearch, approach and method, please read:

A Bio-Mechanical Approach to Dystonia
An introduction to the theory and analysis that support the pilot research project to use an adaptive intraoral appliance to treat and possibly cure Secondary Idiopatic Cervical Dystonia.

The Molar Lever
Our analysis of the bio-mechanics of the Molar Lever and how dental occlusion is related to posture and skeletal allignment.

Phases of Lateral Postural Colapse
Our analysis of the descending skeletal and postural effects of a collapsing and twisting skull that does not find adequate support in the dental arches.

The Rectifier
A description of the adaptive intra-oral aplliance -dental splint – that we use to treat Cervical Dystonia and the orthopedic forces that it produces by progressively pushing the mandible in retrusion, maxila in extrusion and elevating the skull by stretching and aligning the cervical vertebrae.

Resources
Bibliography and links to scientific research on the treatment of Dystonia and other neurological movement disorders with a bio-mechanical approach.

Postural Colapse and Dental Arches
A set of animations that present grafically the type of skeletal and postural effects that we intend to produce over a few months by modifying occlusion and the direction of forces between the skull and the mandible.

Beginning of Treatment
Postural analisys, MR evidence and description of the situation of our patient at the beginning of this experimental treatment.

First Rectifier: Cross-Bite Splint with Lateral Moral Lever Effect
Description of the dental splint that we are using for the first two weeks of treatment and the logic behind the selection of the direction and nature of the orthopedic forces that it produces.

Iatrogenic Damage: When the Dentist is a Butcher
Our review of how modern dental theories on occlusion oversimplify and misunderstand the biomechanics of the  stomatognatic system, leading to a high potential of traumatic dental treatments.

What is Dystonia?
A short description of the symptoms and clinical definition of Dystonia for those who are not familiar with this desease.

Team
Curricula of the team of professionals who are participating and contributing to this research project.

Patients
Please read this page if you are suffering from Cervical Dystonia and wish to try this experimental biomechanical treatment and be a part of this research project.

Fund Raising
Please read this page if you wish to support this research project financially.

5 thoughts on “The Molar Lever

  1. Pingback: First Rectifier: Cross Bite Splint with Lateral Molar Lever Effect | Dystonia

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  4. Pingback: Treatment of TMD with the Molar Lever | Bio-Mechanical Dystonia

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