Specialist article: Face
Facial asymmetry and crooked jawWhen the centre shifts
One half of your face looks wider, your chin is crooked, your lower jaw deviates to the side when you open your mouth? Here you can find out why no face is a mirror image, when a crooked jaw is more likely due to position than to bone shape, what role the chewing muscles and tongue play, and how training breathing, swallowing and head balance comes in.
Does this sound familiar?
Your face looks crooked, and you are wondering why?
What applies to you?
Tap whatever applies to you.
If several points apply, it is worth taking a close look at how your lower jaw is guided. Facial asymmetry has different levels: the shape of the bones, the position of the lower jaw and the tension of the muscles. Position and tension depend on patterns, and patterns can be trained.
Position or shape?The tongue as a pivotThe key points at a glance
- No face is a mirror image. Slight differences between the two halves are normal; most often a difference is noticeable at the chin.
- A crooked lower jaw is not necessarily a bone that has grown unevenly. Often the lower jaw is shifted out of the centre because chewing muscles pull unevenly and the tongue, as the inner pivot, has too little tension.
- In our view, the approach is therefore to address the interplay, not one side. Training breathing, swallowing and head balance can create the conditions under which position and muscle tension reorganise and the lower jaw finds its way back into balance.
Video
Crooked jaw and facial asymmetry: understanding the causes
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Symmetry
Asymmetrical face: no face is a mirror image
Anyone who mirrors a photo of themselves is often startled. The mirrored image looks strange because the two halves of the face are never exactly the same.
Facial asymmetry refers to differences between the left and right halves of the face in size, shape or position. A certain degree of this is part of every face. The eye rarely perceives it, and it bothers nobody. A noticeable asymmetry is not a sign of disease. In our view, however, it is an indicator that breathing, swallowing and head balance have fallen out of balance. It is worth taking a closer look if it increases, is accompanied by complaints or is on your mind.
particularly well-balanced faces showed measurable differences between the two sides on X-rays. Towards the skull they became smaller1
of 1,460 people examined at a university clinic for jaw and facial deformities in the USA had visible facial asymmetry2
of these asymmetries affected the chin, 36% the midface including the nose, and only 5% the upper face2
So the further down the face, the greater the differences. The chin sits on the lower jaw, the only movable bone of the skull. A Japanese analysis of 1,800 orthodontic patients found that where the chin deviated, it deviated to the left in around 79 % of cases. The authors consider this lateral tendency more likely to be congenital than acquired3. A review describes asymmetry as common and often below the visible threshold4.
Crooked jaw
Crooked jaw: position or shape?
Many people are told that one half of their jaw is longer than the other. That does happen. Often, however, it is not the bone itself that is crooked, but its position.
The lower jaw hangs from two joints and is held in place by muscles. If they pull evenly on both sides, it sits centred beneath the skull and the rows of teeth fit together. If they pull unevenly, it shifts to one side.
This shows first at the midline. The centre of the lower incisors no longer lies beneath the centre of the upper ones, and the chin moves with it.
In these adults, then, the difference lay in the position, not in the shape of the jaw. This matches what we observe in practice. In our view, facial asymmetry usually arises from a shift of the lower jaw that muscles develop over years. A bone that has grown unevenly is less common and should be checked by a doctor.
Self-test in front of the mirror: slowly open your mouth as wide as is comfortable. What does the tip of your chin do?
Chewing muscles
The muscles that pull on the lower jaw
Chewing, swallowing and speaking require fine movements of the lower jaw in all directions. For this, several strong pairs of muscles attach to it.
On the outside lie the masseter at the cheek and the temporalis at the temple. Both close the jaw with great force. On the inside, behind the ramus of the jaw, lie the pterygoid muscles. They push the lower jaw forwards and to the side.
All of these muscles come in pairs, one on the left and one on the right. The centre of the lower jaw results from the balance between the two sides.
This balance shifts easily in everyday life. If you prefer to chew on one side, sleep on the same side, prop your head up while reading or hold your head at an angle while working, you load the muscles on the two sides unevenly. In our view, however, what matters is not the individual habit, but whether the lower jaw has a centre to return to.
The bone is not too long. The lower jaw is pulled off centre.A muscular shift develops over years. It continues as long as the pattern producing it carries on.
Tongue reference position
The tongue as the pivot of the lower jaw
The chewing muscles pull from the outside. From the inside, the tongue holds against them. In our model, it is the abutment around which the lower jaw centres itself.
In the tongue reference position, the tip of the tongue rests on the small ridge behind the upper incisors and the body of the tongue lies against the palate with tension. After every swallow, the tongue returns to this shape, many hundreds to a thousand times a day. More on this in the article Tongue resting posture and tongue reference position.
Like a tent with a centre pole
A tent stands straight when the centre pole bears the load and the guy lines are equally taut on both sides. Without the pole, one slightly tighter line is enough and the tent tips to the side. This is how we see the lower jaw. The chewing muscles are the lines, the tensed tongue is the pole in the middle; the technical term for this is hypomochlion, pivot point.
When the tongue rests against the palate with tension and the lips are closed, the lower jaw finds its position. If the tongue drops, for example because the mouth is open, the inner pivot is missing.
Then the outer muscles alone determine where the lower jaw sits, and small differences between left and right gain weight.
With mouth breathing, this tongue tension is largely absent, because the tongue has to clear the way for the air and lies low. That is why, in our view, mouth breathing stands at the start of many causal chains that can lead to asymmetry. The swallowing pattern is part of this too. If someone swallows with the tongue between the teeth, the pivot is missing with every swallow.
Chain of cause and effect
How a shift becomes an asymmetry
In our view, a visible facial asymmetry rarely comes first. It is rather the end of a development that begins early.
The control pattern deviates
Mouth breathing, a low-lying tongue without tension, a swallowing pattern without tooth contact or a head balance off centre. This often begins in childhood.
The chewing muscles take over
Without the inner pivot, the outer muscles guide the lower jaw on their own. One side pulls harder and the jaw shifts to the side when closing.
The nervous system stores the solution
The shift becomes the habitual position. Many hundreds of swallows and bites a day confirm it without you noticing.
Tissue adapts
Tooth contacts, jaw joints and soft tissues adjust to the new position. In children, the position can also become a shape over time.
The asymmetry becomes visible
The chin is off centre, one cheek looks fuller. In many people, this is accompanied by complaints in the jaw, head or neck.
The chain shows why we speak of harmonising rather than correcting one side. In our view, the asymmetry is not the cause but the visible result of a pattern. Where it begins differs from case to case. The fact that it develops over years also explains why change does not come within weeks.
Children
In children, position shapes the bone
During growth, the jaw is malleable. What the muscles and tongue impose on it can therefore be reflected in the shape of the bone.
of the 401 children examined at a Brazilian outpatient clinic for mouth breathers had a lateral crossbite, almost 30 % in the primary and mixed dentition, 48 % in the permanent dentition. More than half had a normal bite relationship6
with unilateral crossbite and a lower jaw shifting to the side were examined in a study in Dallas. The lower jaw was longer on the side without crossbite. After expansion of the upper jaw, no significant shape asymmetry was measurable any more7
In a lateral crossbite, the upper back teeth on one side bite inside the lower ones instead of outside. To bring the teeth together, the lower jaw often shifts to the side.
The Dallas study shows that in childhood this position can turn into a measurable shape asymmetry, and that with early treatment it can even out again. Paying attention early to mouth breathing, the tongue and swallowing is therefore worthwhile.
If you notice a crooked bite, a chin shifting to the side or a constantly open mouth in your child, have it looked at by an orthodontist. The training can be combined with braces. How children practise is explained under FaceFormer for children.
Head balance
Jaw and neck work together
The lower jaw never moves on its own. With every opening and closing, the throat and neck muscles work along with it.
A research group in Hangzhou recorded the activity of the masseter, the floor of the mouth, the sternocleidomastoid and the trapezius in people with developmental mandibular asymmetry. The sternocleidomastoid and masseter worked together, and in those affected considerably more asymmetrically than in healthy people8.
The authors consider it possible that this uneven activity contributes to pain in the jaw joint and neck. The coupling is established; the direction remains open.
of 352 children with an asymmetry at the junction of the head and cervical spine had orofacial dysfunctions in a Hamburg study. This is a correlation in a selected group, not a therapy study9
For us, this means that an asymmetry in the face rarely lies in the face alone. If the head is tilted or held forward, the lines of pull that guide the lower jaw shift. Conversely, a shifted lower jaw pulls the neck muscles along with it. Anyone who only works on the jaw leaves head balance out of the picture.
Consequences
What can go along with a crooked lower jaw
A crooked jaw is more than a question of appearance. Because the jaw, tongue, airways and neck are connected, consequences often show up in several places.
One-sided chewing
One side takes on more work, the muscles on that side become stronger and the shift increases.
Uneven facial features
The chin is off centre, one cheek or corner of the mouth looks different from the other side.
Jaw joint
Clicking, grinding or pain, because the two joints are loaded unevenly.
Head and neck
Tension, headaches and a tilted head balance, which can reinforce each other together with the jaw.
Teeth
Uneven tooth contacts, wear on one side and a bite that no longer feels right.
Breathing
An open mouth, mouth breathing and a low tongue often belong to the same pattern.
If an asymmetry appears suddenly, noticeably increases in adulthood, or is accompanied by swelling, numbness or paralysis in the face, it should first be checked by a doctor. The same applies to infants with a tilted head posture. The training can complement treatment, for example with targeted pull exercises in facial paralysis.
Putting treatments into context
Braces, splint, surgery: what they change
There are several established treatments for a crooked jaw. They address shape and position, and we say openly where we see them differently.
Orthodontics
Moves teeth and can guide the growth of the upper jaw in children, for example with a crossbite. Afterwards, a retainer is supposed to cement the result, because it is assumed that the teeth will otherwise move back. But teeth do not move by themselves; forces are acting. The retainer counters them from the outside and can additionally irritate the tongue.
Occlusal splint
Imposes a position on the lower jaw from the outside. You bite down, but the splint does not provide real guidance, and the masticatory muscles tend to be triggered rather than calmed. In our view, the load shifts to muscles and joints, and when you take the splint out, the habitual control continues.
Jaw surgery
Repositions the jaws in relation to each other in cases of pronounced skeletal asymmetry. If, on the other hand, the jaw is crooked because of position and muscle pull, we consider surgery a bad idea, because it does not address the cause. More under Jaw surgery (BiMax).
All three change shape or position. They do not change the pattern that guides the lower jaw, that is, tongue reference position, swallowing, breathing and head balance. As long as this pattern continues, the same forces continue to act. In our view, this explains why teeth can move back after treatment and why old movement patterns work against the new position after an operation.
A treatment can establish the position. Function has to hold it.That is why medical and orthodontic treatments can be combined with training the basic functions.
If you wear a splint, braces or a retainer on medical advice, do not stop any of them on your own and discuss changes with your practice. With a retainer, in our view it is worth gradually shifting the support inwards, with tongue reference position, swallowing and nasal breathing. You can read how the training relates to other procedures under FaceFormer and other treatments.
Training
Harmonising instead of fighting symptoms
A lower jaw that has been pulled off centre for years cannot be put back with a resolution. What has to change is the pattern that guides it.
FaceFormer training works on the basic functions of breathing, swallowing and head balance, and in doing so on the tongue as the inner pivot. The FaceFormer sits in the oral vestibule behind the lips. In the basic exercise, you press the lip wedge, bite down briefly and swallow. The negative pressure draws the tongue to the palate, and the lower jaw closes from its centre.
In the pull exercise in varying directions, you pull the lip wedge to the side, to the right, to the left or diagonally, and swallow at the same time. Among other things, the exercise is used to centre the lower jaw during swallowing.
Which direction suits your starting position is best decided in consultation with a practice. Without this consultation, stick to the forward pull exercise.
- From day 1
Basic exercise
Three times a day for a few minutes with the FaceFormer ZERO. The free app guides you.
- From around week 3
Pull exercise and night
The pull exercise is added, in varying directions after consultation. At night you wear the ZERO once the basic exercise is established.
- After a few weeks
Switching to the ONE
During the day, you train with the FaceFormer ONE. It is the same size and shape as the ZERO, just made of firmer material.
- Further on
Head balance
With the head balance rotation, you include head balance in the routine.
- Over months
The pattern runs by itself
The exercise manual allows six to twelve months until the new sequences run without thinking, followed by maintenance training.
In our experience, a lasting improvement is also possible without an invasive procedure if the asymmetry has developed from disturbed basic functions and you train consistently. How far position and face change in the individual case cannot be predicted.
There is no study that has examined FaceFormer training in facial asymmetry. The absence of a study does not mean that the connection does not exist; it simply has not been tested. What is available on the training can be found under Studies and science.
Everyday life
Relieving the lower jaw in everyday life
Chew on both sides
Notice whether you prefer one chewing side, and consciously spread the work across both sides.
Tongue to the palate
Between meals, the tip of the tongue rests at the reference point, the lips are loosely closed and the teeth are without pressure.
Breathe through your nose
Nasal breathing keeps the mouth closed and gives the tongue its place on the palate.
Don’t prop up your head
Resting your chin in your hand while reading or at the screen pushes the lower jaw to one side. Set up your workspace so that your head can balance freely.
Skip chewing gum
Constant chewing trains exactly the muscles that already pull strongly and gets in the way of forming a new pattern.
Patience with the pattern
What has developed over years reorganises over months. You have to keep at it, and it can be worth it. Regular practice counts for more than individual long sessions.
Questions
Frequently asked
Is an asymmetrical face normal?
Yes. No face is a mirror image. Even particularly balanced faces show measurable differences between the two sides on X-rays. The largest differences are found in the lower face, most often at the chin. A noticeable asymmetry is not a sign of disease, but in our view it is an indication of an imbalance in breathing, swallowing and head balance. It is worth taking a closer look if the asymmetry increases, is accompanied by complaints or the lower jaw deviates to the side when opening.
What causes facial asymmetry?
There are congenital and acquired causes, such as uneven growth, injuries, paralysis or diseases of the jaw joint. In our view, however, the usual underlying cause is often a displacement of the lower jaw that muscles develop over years. Mouth breathing, a tongue without tension and disturbed head balance stand at the beginning of many such causal chains.
With a crooked jaw, is one half of the jaw longer?
That does happen, but less often than is commonly assumed. In a study of adults with a unilateral crossbite, the lower jawbone itself was symmetrical; it was merely rotated in relation to the skull. Whether shape or position is behind it can be clarified by an orthodontic examination.
What role does the tongue play in a crooked jaw?
According to our model, the tongue is the inner pivot of the lower jaw. When it rests against the palate with tension in the tongue reference position, it holds against the pull of the chewing muscles from the inside. When it lies low, for example with mouth breathing, the outer muscles alone determine the position, and small differences between left and right gain weight.
Does a crooked jaw have to be operated on?
That depends on the cause. If the bone has grown markedly unevenly, surgery can make sense; discuss this with your practice. If the lower jaw is displaced because muscles pull unevenly, we consider surgery a bad idea, because it does not address the cause. Training the basic functions addresses this pattern and can create the conditions under which position and tension reorganise; a particular result cannot be promised.
Does chewing muscle training help with facial asymmetry?
In our understanding, biting and chewing exercises can even do harm. They run outside the physiological pattern of swallowing and tongue reference position and mainly strengthen the muscles that close the jaw, that is, often exactly those that already pull unevenly. In this way, they can cement the imbalance, as we also see in TMD. The brief biting in the basic exercise, by contrast, is part of the swallowing sequence and not a strength exercise.
How long does it take for something to change?
A displacement that has developed over years does not reorganise itself in weeks. The exercise manual expects six to twelve months until new sequences run without thinking. How position and face develop varies from case to case.
Can I train with braces or a splint?
The training can be combined with orthodontic treatment; with fixed brackets, dental wax helps. We see the bite splint in a fundamentally different way from the prevailing teaching. It imposes a position on the lower jaw from the outside, but does not guide it, and the masticatory muscles work against it. If you wear a splint on medical advice, agree with your practice how to divide your time between the splint and the training.
More articles from the knowledge section
Where to go next
Sources
- Peck S, Peck L, Kataja M (1991). Skeletal asymmetry in esthetically pleasing faces. The Angle Orthodontist 61(1):43-48. PMID 2012321. Severt TR, Proffit WR (1997). The prevalence of facial asymmetry in the dentofacial deformities population at the University of North Carolina. International Journal of Adult Orthodontics and Orthognathic Surgery 12(3):171-176. PMID 9511487. Source
- Haraguchi S, Iguchi Y, Takada K (2008). Asymmetry of the face in orthodontic patients. The Angle Orthodontist 78(3):421-426. PMID 18416611. Source
- Thiesen G, Gribel BF, Freitas MP (2015). Facial asymmetry: a current review. Dental Press Journal of Orthodontics 20(6):110-125. PMID 26691977. Source
- O’Byrn BL, Sadowsky C, Schneider B, BeGole EA (1995). An evaluation of mandibular asymmetry in adults with unilateral posterior crossbite. American Journal of Orthodontics and Dentofacial Orthopedics 107(4):394-400. PMID 7709904. Source
- Souki BQ, Pimenta GB, Souki MQ, Franco LP, Becker HM, Pinto JA (2009). Prevalence of malocclusion among mouth breathing children: do expectations meet reality? International Journal of Pediatric Otorhinolaryngology 73(5):767-773. PMID 19282036. Source
- Pinto AS, Buschang PH, Throckmorton GS, Chen P (2001). Morphological and positional asymmetries of young children with functional unilateral posterior crossbite. American Journal of Orthodontics and Dentofacial Orthopedics 120(5):513-520. PMID 11709670. Source
- Dong Y, Wang XM, Wang MQ, Widmalm SE (2008). Asymmetric muscle function in patients with developmental mandibular asymmetry. Journal of Oral Rehabilitation 35(1):27-36. PMID 18190358. Source
- Korbmacher H, Koch LE, Kahl-Nieke B (2005). Orofacial myofunctional disorders in children with asymmetry of the posture and locomotion apparatus. International Journal of Orofacial Myology 31:26-38. PMID 16739710. Source
Get started
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FaceFormer ZERO + ONE
Both material hardnesses for getting started, day and night. The set for adults.
FaceFormer ZERO
The softer FaceFormer for getting started, for children and for the night.
FaceFormer ZERO Children’s Set
ZERO with hygiene box, plush bag and success book with stamp.
FaceFormer training aims to restore the physiological setting of the basic functions of breathing, swallowing and head balance, with lip closure and the tongue reference position, thereby creating the conditions under which symptoms can improve. It does not replace a medical assessment. You can find practitioners near you in the practitioner directory.
