About Bruxism

Dear readers and friends, I post here below a simplified approach to my understanding of “Bruxism” as a form of oromandibular dystonia ad its relation to TMJ.

The post includes a possible treatment and instruction on how to build a lower splint to treat Bruxism.

The proposed treatment is inexpensive, completely reversible, not traumatic and -most importantly- can be executed by patients on their own, at their own home.

Please tear my “theory” to pieces in the comments below … and also tell me what makes sense according to you.

Natural healhty mouth never touched by a dentist compared to one treated by dentists

Natural healhty mouth nevert ouched by a dentist compared to one treated by dentists


The above picture shows the comparison between a natural healthy skull and mouth -never touched by a dentists- and a mouth which has clear signs of the result of extractions, treatments performed by a dentists and bruxism. Let’s use the image as a reference throughout this post.

I believe that nobody can deny 5 facts:

  1. All natural healthy mouths never touched by a dentist have a natural movement between TWO positions which are usually around 2mm apart: Centric Relation -CR- (first contact of the teeth) and Max Intercuspation -MAI- (full contact of the teeth with max chewing muscle contraction).
  2. This movement is articulated by contacts between opposing molar and premolar teeth.
  3. Max Intercuspation (MAI) is usually 2mm forward from CR and in many mouths even LATERAL
  4. In natural mouths MAI has a rock solid interlocking of the teeth, with lateral, torque, diagonal, mesial, distal contacts between teeth of the opposing arches. When the mouth closes with max muscular contraction, the mandible can not move even a fraction of a mm.
  5. The cusp-fosa relation in contact between opposing teeth follows the curves of the condyles (lower fossas have the curve of the glenoid fossa and upper cusps reproduce the curves of the head of the condyles


For some reason (which I find insane) that goes beyond logic or understanding, the great majority of dentists apply a model of occlusion based ONE position.

Most dentists and dental schools think that nature is wrong and that the correct way for a mouth to close is:

  • Like a door where the condyles move in rotation as “hinges.”
  • With only vertical contacts between opposing teeth.
  • With “freedom in centric” – which is a way to define that the mandible should be able to move a few mm in any direction without lateral tooth contact when chewing muscle contract ti the maximum.
  • Without cusp-fossa relation between opposing teeth that create retrusion stops and prevent the lateral derangement of the condyles and disks of the TMJ.
  • With a flat curve of Spee.
  • In a retruded position of the condyles and mandible – in Centric Relation.

Most dentists consider that the contacts that articulate movement between CR and MAI are “prematurities” or “interference” and should be eliminated.

They think that the condyles do not need the teeth to provide a guide, retrusion and lateral stops.


In essence what dentist call “bruxism” is a neurological movement disorder, a form of oromandibular dystonia. The mandible goes “crazy” because it can not find a stable position of Max Intercuspation.

Patients (and sadly most dentist) may think that “bruxism” is a well defined, scientifically researched condition or disease (like pneumonia or the flu). It isn’t. The definition of “bruxism” by dental schools is tautologic.

A tautologic definition is one that uses formal logic, but is redundant and self fulfilling. For example: “A sunny day is a day when the sun is in the sky.”

By definition, if the oversimplified theories and myths of occlusion described above create instability in a patient’s mouth, it is because he is a “bruxist.” Please note that dental schools know that their oversimplified model does not work on a significant number of patient’s mouths.

The reality is that “Bruxism” is caused by a dental trauma (usually originated or aggravated by a dentist) that has caused dental occlusion to collapse from TWO positions to ONE position.

The autonomous (involuntary) nervous system will try to find a different, second position where teeth have grip to allow a stable contraction of all muscles to carry out the act of swallowing.

We swallow about 2000 times a day. During sleep, this involuntary reflex is triggered once every minute.

As we saw before, the acts of chewing and swallowing are carried out in natural mouths (i.e. never touched by a dentist) in TWO very different positions. And that happens because the mandible works biomechanical in TWO very different ways in those TWO positions.


The best option to treat bruxism is to to recover a natural position of Max Intercuspation where teeth interlock firmly and provide a solid grip for muscles to contract when swallowing.

Upper splints are dangerous and inherently imprecise as they do not allownfor the movement of cranial bones (we may expand on the subject in another post). The best option is to register a MAI bite by covering a lower base splint with polymorph or self curing resin. It should be done directly in your mouth (not the articulator which is imprecise and based on the wrong model) while you sit straight and close your mouth in the position that is produced by pronouncing the letter “E” or “O.” or “AH”. Those positions force the muscles to stretch in a symmetric way, therefore pushing the mandible in the desired balanced swallowing position.

After the patient has reproduced a minimally stable Max Intercusption on a lower splint, it is time to start neurological rehab and specific exercise for the tongue.


Please read at point 6 of the post on Principles of Splint Therapy to find how-to videos and instructions on how to build your own splints.

It takes one hour to learn and master how to register a bite on it (trial and error), but in the end it is a piece of cake and the Do-It-Yourself slints you will make will work much better than any splint a dentist can make. That happens  beacuse you will be able to adjust the splints at will as your skull adjusts to the new occlusal realtion created bu the splint.

Natural teeth have condylar shape. If you look at the picture above, you will see that the protection, guidance, retrusion stops for the TMJ is provided in natural mouths by:

  • 32 teeth.
  • A very pronounced curve of Spee (allmost a section of a circunference).
  • 64 molar and premolar cusps.
  • 6 very pronounced lower molar fossas.
  • Anterior incisive guidance which breaks drammatically the curve of Spee.
  • Functional and balancing contacts that allow the mandible to have multiple (more than the minimum 3 points that define a plane) functional and balancing contacts in all positions of the mandible.
Condylar shaped teeth

Condylar shaped teeth

When a mouth has been traumatized by extractions, equilibration, age, use and the natural curves and cusps have been flatened… all you can do is try to recover the function in the best way given the cirmustances.

Building 4 deep lower pits that fully embrace the upper molar and premolar cusps are the way that I have found to try to reproduce the function of the curves that is lost. It is also advisable to build balancing contacts in poliforph on the incisives.

But the most important issue is that it is necessary  to reproduce on the lower splint 4+4 deep round PITS on molars and premolars that fully embrace lingual cusps of the uppermolars and premolars and a sliding controlled and bilaterally balanced guide from the points of first tooth contact with the splint (CR) to the final point where cusps are fully embraced (Max Intercuspation). Thus, the splint will guide the mandible towards a rock solid fixed MAI position.
If it is well done, it does not matter much if you use resin (harder) or polymorph (softer).

A lower splint with pits that fully embrace upper molar and premolar cusps

A lower splint with pits that fully embrace upper molar and premolar cusps.

Be advised that the picture above reproduces a Gelb-Rectifier splint that does not have contacts between incisives in the front. It is advisable to use this kind of splint for the first part of the treatment (until the neurological movement  instability of the mouth is fully discontinued). Afterwords, for a long term stable splint, I would advise to reproduce with polimorph incisive and canine balancing contacts and guidance  for protrusion and lateral excursion.


As Far as how to reproduce protrusion and retrusion ramps on polimorph to guide the mandible in the movement from CR to MAI to Protrusion, this is my system:

  • Register the bite on polimorph in phonetic “o” Max Intercuapstion position first.
  • Let the splint cool down and the polimorph harden.
  • Put the splint again in hot water for only 10 seconds to soften the polimorph.
  • Register a bite in “E” phonetic (close to CR) without biting to hard (just first touch).
  • When the splint has cooled down, use a small kitchen knife to engrave a shallow connection between the points where the cusps have made contact in the two bite registrations.

The whole process takes 3 minutes. An you can do it again and again if it does not fell right in the mouth


In conclusion: “Bruxism” is a form of neurological movement disorder caused by the absence of non vertical contacts (be it lateral, diagonal, torsion or torque) between antagonistic teeth of the opposing dental arches that provide a stable “grip” for the muscles to contact during the act of swallowing.

These contacts between”condylar shaped” molar teeth are also necessary for the TMJs to function properly as they provide protrusion and lateral guidance and restrusion stops.

Most of the times “Bruxism” it is caused or aggravated by dentists who act upon the false belief that during chewinging and swallow the teeth have to occlude in the same position and collapse MAI into CR with a dental drill.

A good way to try and treat Bruxism is by building a lower splint that creates  a rock solid and fixed Max Intercuspation 2 mm forward with respect to Centric Relation and reproduces the curves and balancing and functional contacts of the teeth in the movement from Centric Relation to Max Intercusption.

Phonetic bite registration on a Gelb-Rectifier splint directly in the mouth allows to find a functional position of Max Intercuspation and Centric Relation.


Navigate Through 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.

Principles of Splint Therapy
A description of the principles on which we base our protocol for the treatment of Cervical Dystonia and other occlusion realated movement disorders with varying degrees of neurological symptoms (from Tourette’s, to postural collapse, Parkinson’s and Generalized Dystonia).

Protocol for the Treatment of Cervical Dystonia
A step by step description of the 3 phases of the DIY protocol that we have developed for the treatment of Cervical Dystonia.

The Molar Lever
Our analysis of the bio-machinics 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.

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.

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