Gnathology 2021-03-15T12:06:15+01:00


Gnathology is a branch of specialized dentistry that studies and cures the masticatory system in all its anatomical and functional aspects.

The objective of this discipline is the identification of the correct cranio-mandibular relationship, its maintenance and / or its restoration in equilibrium with the functional and muscular activity.

There is a close relationship between the correct contact between the two dental arches, the mandibular muscles and the cranio-mandibular bones.  Gnathology is concerned with studying and restoring the correct balance between these zones and solving the resulting symptomatology.


Physiologically, the movement of the jaw takes place freely, without  tiring the structures connected to it. In cases of malocclusion and / or temporomandibular joint disorders/ or masticatory muscles, this movement is no longer free, with frequent symptoms such as: pain in the facial and odontogenic areas, trigeminal pain, headaches, neck pain, dizziness, phonation, disturbed hearing, and can generate imbalances in posture. A gnathological examination can highlight the presence of malocclusion,temporomandibular joint disorders (DTM) or cranio-cervico-mandibular disorders (DCCM).The tests and instrumental examinations available to specialist clinicians are manifold  (X-RAY, 3D CT scan, magnetic resonance imaging,mandibular kinesiography, surface electromyography, kinesiological tests…).  Following a careful examination of the clinical history and diagnosis, the therapy used in gnathology consists of resin devices which will lead the joint to the specific therapeutic position, as well as restore muscle balance through the myocentric position. These devices are known by the generic name of “BITE” but always require a preparation based on each specific case, as well as, appropriate checks-ups.

At our centre, it is possible to perform a correct diagnosis, thanks to specialized clinicians and the help of advanced technology that allow specific tests to be performed on site.

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The bones of the skull and  jaw are connected to each other thanks to the temporomandibular joint, this double joint allows all the movements of the jaw and is therefore essential for speaking, eating, swallowing etc. When the mouth is opened the condyles, i.e. the rounded ends of the jaw, rotate in the cavity of the temporal bone moving forward. Instead, when we close the mouth the condyles return to their original position. Between the temporal bone and the condyle there is an articular disc (called meniscus) consisting of fibro-cartilage that acts as a  cushion and allows a smooth and homogeneous movement.

When this movement no longer occurs correctly, it is called Temporo – Mandibular Disorder (TMD). The causes can be various: genetic or congenital cranial asymmetries, malocclusions and therefore  contact between incorrect dental arches or poorly aligned teeth, direct or indirect trauma, wrong dental therapies, bruxism, stress clenching or onychophagy. Symptoms can vary from person to person, you can have: blockage of the jaw, chronic pain in the face muscles, headaches, neck pain, odontogenic and trigeminal pain, dizziness, hearing problems. With an accurate gnathological examination and with specific tests, you can identify the temporomandibular joint disorder, evaluate the possible triggering cause and start therapy with individual devices, closely studied for the specific case. The “bite”  has the task of restoring the correct movement of the jaw, as well as recreating a neuro-muscular balance. The patient wearing the bite will immediately feel its beneficial effects with a progressive reduction of  the symptoms.

At Omniadent centre,  Bites are designed using diagnostic tests, specific to the individual case, performed directly on site, such as X-rays or CONE BEAM CT (CBCT) of the Temporo Mandibular Joints, Electromyography with Tens, Kinesiography, postural evaluations, which  allow a global approach and to personalize each  specific problem.


The term Cranio-Cervical Mandibular Disorder refers to a neuromuscular condition, especially of the head and neck, determined by numerous factors that can causes or be contributing factors to: trauma, genetic or congenital skeletal asymmetries, temporomandibular disorders, malocclusions , dental frame and / or bruxism, inappropriate dental care etc. etc … The symptoms of cranio-crevic-mandibular disorders can vary and be of different intensity and often require the intervention of various specialists. The patient with cranio-cervico-mandibular disorder is often unable to intercept the nature of his disorder, arriving at the gnathological examination only after having seen several other specialists. Among the most frequent symptoms are pain in the chewing muscles that radiates in the cervico-facial muscles, or vice versa, pain in the temporomandibular joints, otological pain, tinnitus, dizziness, eye disorders and severe trigeminal neuralgia. Cranio-cervico-mandibular disorder is often accompanied by dysfunction of the temporomandibular joint with more or less marked difficulty in moving the jaw and chewing. With an accurate gnathological examination, the specialist can identify the current Cranio-Cervico-Mandibular Disorder by assessing the dental, mucous, muscular, articular and extra-oral conditions, by anamnesis and a visit. It will also be possible to highlight relevant or determining postural problems in this pathological condition. For a complete diagnosis, specific diagnostic tests (3D morphological CT analysis, kinesiography and surface electromyography) will also be necessary. The therapy for cranio-cervico-mandibular disorders requires, above all, a careful and multidisciplinary diagnosis  in the gnathological field. The restoration of muscle-articular balance takes place thanks to individual intraoral repositioning plates, called “bites” that eliminate inadequate dental contact, balance the occlusion, avoid  clenching and grinding of the teeth, reposition the joints in a therapeutic position, allowing  relaxation of the jaw muscles and  restoration of a correct activity of the agonist muscles.


Instrumental exams

Various supporting tests are performed to diagnose gnathological disorders affecting the muscles and the temporomandibular joint. They include electromyography and kinesiography. These are tests that allow a precise assessment of the functional state of muscles and the temporomandibular joint :

  • Electromyography (or EMG): it is a neurophysiological examination that, through the use of electrodes, measures muscle bio-electric activity at rest and in activity. It is used to identify anomalies affecting specific muscles, as well as assessing the overall activity of different muscle groups.

EMG can highlight through graphs, any anomalies of the nerve, muscle, neuromuscular junction, permitting the study of the type, location, severity and duration of the pathology.

EMG examination should be considered as an extension to the clinical examination.

  • Kinesiography (or KNG) is a method that obtains both the habitual occlusion (physiological) and the individual occlusion, oriented according to the activity of the muscles.
  • A technique using an instrument that exploits the variation of specific magnetic fields and that is able to provide the trajectory of the mandibular movement in its three directions. By evaluating the mandibular movements and their speed of execution, it is possible to identify the presence or absence of intra-articular lesions or condyle-meniscal incoordination.
  • Kinesiography (or KNG) is a method that obtains both the habitual occlusion (physiological) and the individual occlusion, oriented according to the activity of the muscles.
  • A technique using an instrument that exploits the variation of specific magnetic fields and that is able to provide the trajectory of the mandibular movement in its three directions. By evaluating the mandibular movements and their speed of execution, it is possible to identify the presence or absence of intra-articular lesions or condyle-meniscal incoordination.


Instrumental exams


Arguments treated in the book by. G. de Nicolo “Dall’otoneurologia alla posturologia statica e dinamica” coautore con dr. P. Ranaudo, dr. F. Grazioli, dr. C. Condorelli



Dentistry, orthodontics and gnathology are odontostomatological specializations that deal with the health of the oral cavity in different areas, but which are all strictly connected. Dentistry deals with the treatment of hard and soft tissues in the oral cavity, therefore with the treatment of caries, periodontitis, replacement of dental elements, and the prosthetic area. Orthodontics deals with the occlusal relationship of the dental arches through the movement of the dental elements and skeletal bases, while Gnathology studies the function of the oral cavity through a wide evaluation that starts from the dental elements, from their position to the muscular and articular functions and to the related metabolic and functional activities.

The oral cavity is one of the most important sub-systems in the complex postural system, due to several factors, since:

  • It relates to the skull and is able to condition its development , what osteopaths call PRM (primary respiratory mechanism), or the physiological movement of the sutures of the skull.
  • It relates to the cervical spine, through muscle function, in particular due to the relationships between the cervical muscles and the suprahyoid and subhyoid muscles, which are conditioned by any disharmony in the mouth and by swallowing.
  • It can condition important functions such as chewing, phonation, swallowing and breathing, which if they do not work with the necessary balance, could affect adjacent metabolic activities, such as visual, neurological, otological, bio-mechanical functions, and even affect peripheral sub-systems that can decompensate, causing symptoms or disharmonies with consequences that affect the posture and often, the daily life of our patients.

Dento-facial asymmetries

The skeletal asymmetries of the face always represent three-dimensional and deep disharmonies of the skull. Considering the bones of the skull as many articulated cogwheels, it is easy to understand that asymmetries are the result of a problem with some of the wheels of the mechanism. (Fig.1)

Posture 1

Posture 2

Fig. 1 –Dento-facial asymmetries

Fig. 2 – Postural view of a lateral occlusal dysfunction

Symmetric cranial ratios lead to a symmetrical occlusion

In fact, it is almost impossible for an asymmetrically distorted functional matrix to shape a subsequent  normal bone growth. There must be an evolutionary advantage, although not always evident, in having anatomical structures around axes of symmetry. It is difficult to grasp the biological advantage of symmetry, even more difficult to ask how far the geometric perfection of this case needs to be pushed for the advantage to  materialize. We do not even know if the left and right structures are represented from a geometric point of view in a situation of absolute potential symmetry, or only relative. The fact is that: the condition of perfect geometric symmetry does not seem to be important in biological terms and therefore does not constitute the norm. This general assumption obviously also applies to the ​​anthropometric and orthodontic field of interest. Each face, however attractive, does not present a level of symmetry perfectly mirrored on the two emilates, but has slight asymmetries. Each dental arch, although harmonious, does not have a level of asymmetry perfectly mirrored on the two emilates, but has slight asymmetries.

Fig. 3 – The asymmetries of the face, the true image is in the centre

The asymmetries of the face, the true image is in the centre

The photo of the “true” female face is the one reproduced in the centre. On the left and right the two composites of the right and left parts of the face duplicated and reflected. If the facial symmetry were perfect, the three images would be the same, which is not the case at all. Although the “true” face is pleasant, it has asymmetries that are hardly perceptible, certainly not pathological, but only geometrically relevant.


Changes that occurred during evolution allow an upright posture that does not cost us enormous muscle energy (although this probably makes us the animal with less physical performance), the weight load is absorbed by the bones with the mediation of articular discs and menisci. The way our body reacts to the force of gravity, or posture, is physiological when the organs responsible for weight load are able to distribute the weight with minimal muscle work and reduced stress on the ligaments. This postural control is neurological and there are several organs intended for this purpose: vestibules, eyeballs, soles of the feet, periodontal receptors, neuromuscular spindles, cut etc.

From a mechanical point of view, our body responds to two needs:

  • solidity to combat gravity and protect the cerebrospinal axis
  • mobility for a life with interrelation and absolute life.

Solidity is the prerogative of three rigid compartments (skull, thorax, pelvis) which have an impressive bone structure and which represent ideal containers to protect our internal organs (brain, lungs, heart, liver, kidneys and genital organs), and have three hanging limbs (jaw, arms, legs). They form the kyphotic curves of the vertebral column (cranial, dorsal, pelvic) and are connected to each other by  two cervical and lumbar lordosis.

Mobility is the prerogative of these two lordotic curves which connect the three rigid spheres together. Lumbar lordosis is the one that differentiates us from all the other animals: it was crucial for the transition to erect posture. Other primates (chimpanzees, gorillas etc.) lack them.

Kyphosis and lordosis are connected by two systems (muscle and fascial) responsible for static and dynamic:

  1. a direct anterior, median system that connects the skull to the sternum and then to the pubis: its activation brings the skull closer to the pubis, that is, it is responsible for the flexion movement
  2. a direct posterior system that connects the skull to the coccyx: its activation moves the skull away from the pubis, is responsible for the extension movement (Fig 4).

Fig. 4 Representative scheme of the system

The dynamics of the human body also requires two oblique muscular systems that are used to connect in the transversal sense anteriorly and posteriorly, the two direct systems and are named :

A: Anterior cruciate system

B: Anterior cruciate system

The task of the cruciate systems is to ensure coordination in the movements.

Fig.5 Representative scheme of the systems

Direct anterior and direct posterior cruciate, anterior and posterior cruciate.

The activation of these two systems allows our body to have a fine regulation of both static and movement, thus allowing us to maintain a correct postural position, that is, with the best possible balance, economy and comfort ratio. The result of the activation of these muscular and fascial systems are a movement with a helical physiognomy: that is, in walking, we load the support on one limb and unload it at the same time from the other, modifying the centre of gravity of the body and therefore allowing a re-adaptation of the various sectors of the body, easily seen at pelvis, shoulder and jaw level as a misalignment (Fig. 6).

Fig. 6 – Posture while walking

Study of physiological posture

For a profile reading, the patient must be positioned with the external malleolus 1 cm behind the plumb line; in this position the physiology of the profile is seen aligned on the plumb line: knee, femur axis, coxo-femoral joint, elbow, shoulder and external acoustic meatus. L3 and C3 should ideally be aligned on the plumb line. The tangent line to the head results physiologically parallel to the Frankfurt plane and the ground plane (Fig. 7).

Fig. 7Anthropometric references with respect to the Frankfurt plane

Observation in latero-lateral posture:

1) head:

  • with external acoustic meatus on the plumb line
  • head moved forward by flexion of the higher cervical
  • head moved forward due to flexion of the lower cervical

2) pelvis: L3 on the plumb line anterior or backward

3) knees: on the plumb line hyper-extended or flexed

4) feet: normal, flat or arched

Fig. 8Reading the antero-posterior posture

In physiological conditions, compared to the plumb line, the right and left half of the head and body are roughly equal; ears, shoulders and iliac crests are at the same height on both sides. It must be remembered that a right-handed person falls a little to the right with respect to the plumb line while the left-handed falls a little to the left.

The most important things to observe for the dentist:

1) head: centred, moved to right or left, inclination, twist

2) pelvis: centred, moved to right or left, inclination, torsion

3) knees: straight, varus or valgus

4) feet: straight heel, right or left valgus heel, right or left varus heel

Fig. 9Podalic support for flat feet and for arched feet

Plantar support study

Figure 8 shows an example of a flat foot characterized by a flattened plantar vault, outstretched forefoot and valgus heel, seen with a podoscope.

Also in figure 8 an arched foot is represented, characterized by an accentuated plantar vault, a contracted forefoot and a varus heel, seen with a podoscope.

Fig. 10Mechanical sequences of flat-valgus feet

Typical attitude of an arched foot: the varus heel favours the presence of valgus and flexed knee, the external rotation of the head of the femur leads to the retroversion of the pelvis (Fig. 10). There is a prevalence  of the posterior muscle chain tone, strong psoas, the contracted spinal and  multifidus stabilize the vertebrae giving a typically tense profile image. Shoulder blades and sacrum are on the same posterior plane and also in this case the head is forward (Fig. 12).

Fig. 11 – Mechanical sequences of arched-varus feet

Fig. 12 – Scheme of typical postural alterations in flat and arched feet



We hear more and more often about people suffering from bruxism, i.e. the involuntary grinding of the teeth that occurs mostly at night during the early stages of sleep but which, especially in conditions of psycho-physical stress, can also occur during the day. Teeth grinding can be of varying duration and intensity. In clinical gnathology bruxism is defined as a parafunction, or a movement that is not aimed at any purpose. Numerous studies are underway to identify the particular cause of bruxism, from stressogenic factors, to an incorrect alignment of the dental arches, up to neurological or skeletal tension of the skull (osteopathic theory). Normally, in rest conditions, the two dental arches do not come into contact with each other, there is a small space of a few millimeters that divides them, (rest position), in cases of bruxism, the resulting muscle alteration involves a continuous contact between the two arches, leading the muscles to overwork which, in addition to causing contractures on different muscles, can cause dental clenching or bruxism, activating a loop. The bruxist patient often reports fatigue in the jaw especially upon awakening, along with other typical symptoms of gnathological problems (headache, pain in the ears, clicks of the jaw).

Bruxism is not a problem to be underestimated, in fact the grinding of the teeth can have important consequences leading to a levelling of the teeth with possible exposure of the dentin, gingival damage and periodontitis, as well as causing alterations to the temporomandibular joint with consequent cranio-cervical mandibular disorders. The solution that is often proposed by the gnathologist specialist, is the use of a customized intraoral device (called bite), which reduces muscle contractures, re-positions the temporomandibular joints into a condition of better and more comfortable functional bite. There is no equal bite for everyone. It is important that the gnathologist  decides which form and the best material to use according to the clinical situation. The patient wears the bite during the hours suggested by the clinician and in most cases, in a short time, an improvement in symptoms and better sleep quality are observed. Over time, the bite could be modified by the gnathologist in order to adapt it to changes and render it still functional


The postural bite is an individual intraoral device that deals with the posturo-functional re-education of the muscles and temporomandibular joints.

After a precise diagnosis of the primary dysfunction, through relative investigations and diagnostic tests, that  are deemed appropriate in the specific case, (see details), our operators will gather the necessary information to allow the technical laboratory to prepare a customized device constructed according to the therapeutic indications that the case requires.

For a correct construction of the bite two sessions are necessary:

  • During the first session, specific impressions and details of the skull are taken, together with all the information collected from the diagnostic tests, that have become necessary and that will make it possible to create the individual product.
  • During the second session, the device will be checked and delivered to the patient, who will be instructed by the clinician on the correct use to ensure the effectiveness of the treatment.

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