World Journal of Dentistry
Volume 11 | Issue 3 | Year 2020

Clinical and Functional Analyses of the Musculoskeletal Balance with Oral Electromyography and Stabilometric Platform in Athletes of Different Disciplines

Bianco Edoardo1, Nanussi Alessandro2, Bellotti Davide3, Attuati Sara4, Maddalone Marcello5

1,2,4,5Department of Medicine and Surgery, University of Milano Bicocca, San Gerardo Hospital, Monza, Italy
3Private Practitioner, Milan, Italy

Corresponding Author: Bianco Edoardo, Department of Medicine and Surgery, University of Milano Bicocca, San Gerardo Hospital, Monza, Italy, Phone: +39 3487268209, e-mail: edoardowhite@gmail.com

How to cite this article Edoardo B, Alessandro N, Davide B, et al. Clinical and Functional Analyses of the Musculoskeletal Balance with Oral Electromyography and Stabilometric Platform in Athletes of Different Disciplines. World J Dent 2020;11(3):166–171.

Source of support: Nil

Conflict of interest: None


Aim of study: No evidence is found in literature to assess that malocclusion can lead to postural or craniocervical–mandibular disorders. The aim of this study is to investigate with surface electromyography (EMG) of masticatory muscles and stabilometric analysis the relationship between malocclusion and presence of temporomandibular disorders (TMDs) or postural variations in a group of athletes of different sports.

Materials and methods: Seventy-four athletes belonging to different sport societies were included in this study. Chi-square test, taking as significance index χ2 > 0.05, was used to compare in pairs the postural interference, muscle disharmony, malocclusion, and TMDs.

Results: No statistical significance emerged, correlating postural interference and muscle disharmony (χ2 = 0.15), muscular imbalance, and anatomical findings of malocclusion (χ2 = 0.62), muscular imbalance and TMDs (χ2 = 0.15), and TMDs and malocclusion (χ2 = 0.09). Statistically significant association [χ2 = 0.019, odds ratio (OR) = 3.10] emerged from the correlation between TMDs and postural interference.

Conclusion: A correlation between posture and occlusion is very difficult to be demonstrated. A multidisciplinary approach is required for TMDs: therapy with oral splints allows to give greater compliance to the system by allowing muscles to guide the jaw in a position of functional equilibrium.

Clinical significance: Gnathological treatment evaluated through EMG and stabilometric platform allows to obtain improvements in the occlusal balance.

Keywords: Electromyography, Gnathology, Occlusion, Orthodontics, Posture, Sport dentistry, Stabilometric, Temporomandibular disorders.


Up to now, in literature, there is no evidence to assess that malocclusion can lead to craniocervical mandibular disorders. Nevertheless, the etiopathogenesis of these problems is due to several factors and a multidisciplinary approach is needed to identify the origins of them.


Athletes stress the musculoskeletal system more and recruit the elevator muscles of the jaw heavily compared to other people, so it is important to evaluate the muscular activity and postural control as well as occlusion stability; this is the reason why they were chosen as statistic sample in this study.1

The electromyography (EMG) is a noninvasive exam which evaluates the masticatory muscle activity by facial application of electrodes on masseter and temporal muscles. In the last 10 years, several studies demonstrated the effectiveness and reproducibility of surface EMG in the objective evaluation of temporal and masseter muscle activities, thus evaluating the effect of occlusion on the muscle balance.210

Stabilometric platform can be used to evaluate the cervical, occlusal, and ocular interference in posture.

There is a growing interest in the relationship between occlusion and posture because of a greater incidence of neck and trunk pain in patients with occlusal dysfunction. This topic was well debated but still no evidence is available in sport dentistry that any kind of gnathologic, orthodontic, or prosthodontic treatment can somehow improve sport performances.


The aim of this study is to investigate the relationship between malocclusion and presence of temporomandibular disorders (TMDs) or postural sway variations in a group of athletes of several sports.


Seventy-four athletes belonging to different sport societies (Dinamo Sassari, CUS Rugby Genova, Gruppo Sportivo Atletica Brugherio, Società Educazione Fisica Torres e Torres Tennis) were included in this study, and the informed consent was obtained to do the research.

The protocol used was based on AIG (Accademia Italiana di Gnatologia—Italian Academy of Gnathology) guidelines, and considered occlusal evaluation, analysis of mandibular movements, and temporomandibular joint (TMJ) clinical exam.

The term malocclusion, in this research, comprehended at least one of these occlusal features: partial edentulism, median line deviation, increased overjet, deep or open bite, crossbite, dental crowding, or classes II and III malocclusions according to the angle.

During the analysis of mandibular movements, mandibular deviation, limitation in opening, protrusion and laterotrusion, pain during the mandibular retrusion were analyzed.

In TMJ, clinical exam was considered the presence of articular noises, irregularities in the condylar movement, sagittal asymmetries, and pain on palpation.

A four-canal surface EMG of jaw elevators muscles (masseter superficial head and the anterior temporal muscle) was obtained by using BTS TMJoint® (BTS Bioengineering) and its percentage overlap coefficient (POC) 4 protocol.

The postural stabilometric evaluation was made with Lizard stabilometric platform (Lizard S.r.l.) with three load cells.

The position of each athlete on the stabilometric platform was repeatable, so that the initial conditions were the same for the whole statistical sample: feet were placed with an inclination of 30° between them; this position is pre-set in the platform with guidance lines (Fig. 1).

Calcaneal tendon, external malleolus, and second root toe were used as points of reference and placed on the traced lines above the footboard.

For each athlete, four postural stabilometric measurements of 51.20 seconds (according to Pierre-Marie Gagey protocols) were obtained in the following conditions:

In the postural analysis, the area and length of oscillation of the body’s center of gravity were evaluated to assess the efficiency of postural strategies of balance control.

Surface EMG was performed using electromyography analysis, according to the validated protocols with two Bluetooth probes on the anterior temporal muscles and two on masseters.

Fig. 1: Positioning of the athlete on the stabilometric platform

The electrodes used were bipolar circular shaped with a diameter of 1 cm and pre-gelled with saline base conductive gel. After cleansing the skin with gauze soaked in 90% denatured ethyl alcohol to remove the sebum, they were placed at the belly of the masseters and along the line parallel to the major axis of frontal bone zygomatic process on the temporal muscles.

A 5-second clenching test was made in these conditions:

The test on cotton rolls allowed to calibrate the electromyograph on the specific patient analyzed. If the calibration were not performed, the investigations would have been influenced by several factors such as cross talk (analysis of the nearby muscles), skin conductivity (variable depending on the tissue composition), skin condition (sweating), and position of the probes. What was analyzed during the calibration is not the occlusion, but the maximum muscle activity expressed as the electrical activity that the muscles can express without the dental contact (ideal condition) (Fig. 2).

This value is used to normalize the data. It means that the software automatically compares the calibration with the subsequent tests and evaluates, through electromyographic indices, how the neuromuscular activity changes once the dental contact is inserted. The software established the role of the occlusion based on the neuromuscular equilibrium, providing the following indices:

Fig. 2: Example of an electromyographic analysis

In the present study it was defined “muscular interference of occlusal origin” a muscular disharmony detected by a surface EMG, performed comparing the ability to clench on dental cotton rolls (without any influence of occlusal contact) to occlusion on teeth. Difference was calculated analyzing the global index of neuromuscular balance represented by a percentage from 0 to 100 and the electromyographic indices aforementioned.


The orthodontic clinical exam showed that 58 of 70 athletes presented with malocclusion problems (Fig. 3).

The TMJ evaluation showed that 42 athletes (87.5%) had TMDs, according to the criteria mentioned above (Fig. 4).

In 30 of 74 athletes, no occlusal interference was observed because there was no differences between electromyographic test on cotton rolls and occlusion on teeth, thus not showing any muscular imbalance.

The analysis of the data obtained from the stabilometric platform shows that in maximum intercuspation 37 of 74 athletes showed increases in the oscillation area with worsening of postural balance, compared to what was observed with the examination carried out on the cotton rolls (Fig. 5).

The statistical analysis was performed with SocSciStatistic software, using the chi-square test, taking as significance index χ2 > 0.05. The following parameters were compared in pairs:

No statistical significance emerged correlating postural interference and muscular disharmony (χ2 = 0.15), muscular disharmony and anatomical findings of malocclusion (χ2 = 0.62), nor muscular disharmony and TMDs (χ2 = 0.15) (Tables 1 to 3).

Not even the association between TMDs and malocclusion shows a level of statistical significance (χ2 = 0.09) and neither the correlation between malocclusion and postural imbalance (Tables 4 and 5).

Fig. 3: Athletes with normal occlusion/malocclusion

Fig. 4: Athletes with/without temporomandibular disorders

Fig. 5: Athletes with/without postural interference

Table 1: Postural imbalance by muscular disharmony
Postural imbalanceMuscular disharmony
Table 2: Muscular disharmony by malocclusion
Muscular disharmonyMalocclusion
No  426300.1527
Table 3: Muscular disharmony by temporomandibular disorder (TMD)
Muscular disharmonyTMD
Table 4: Malocclusion by temporomandibular disorder (TMD)
No  412160.0962
Table 5: Postural imbalance by malocclusion
Postural imbalanceMalocclusion
Yes  63137
Table 6: Postural imbalance by temporomandibular disorder (TMD)
Postural imbalanceTMD

The only significant association (χ2 = 0.019, OR = 3.10) emerged from the correlation between TMDs and postural interference (Table 6).


The 87.5% of the athletes that had a malocclusion diagnosis suffered from TMDs; however, it is not possible to find a correlation between these parameters because there is a high percentage of TMDs even in the group with a normal occlusion. It is important to underline that a bad dental alignment can have no functional consequences, on the contrary, people with altered mandibular skull relationship hidden by a good dental alignment can manifest functional problems. Indeed, the term malocclusion also comprehends an incongruous cranial–mandibular spatial relationship.1113

In some cases, dental alignment can influence the position of the jaw and can determine a postural adaptation, mainly at a craniocervical level.

Data analysis shows that malocclusion could not be an etiological cause of TMDs. Temporomandibular disorders have many etiological factors: occlusal or skeletal disharmonic relationships, degenerative diseases, rheumatologic, endocrine, or postural alterations. The predisposing factors, though, cannot generate the pathology without the contribution of triggering factors such as parafunctions, traumas, or incongruous therapies. Also structural or psychological factors have to be added.

It is necessary to say that the population taken into account by the authors is that of healthy young athletes; they stress the musculoskeletal system more and recruit the elevator muscles of the jaw heavily than other people so results in different population may differ.

Stomatognathic system is considered to be fundamental in postural control. Rugh et al. in 1981 demonstrated that in rest position the electromyographic activity of the muscles is at its minimum, indeed gravity strength is balanced by elevator muscles and soft tissues.14 The interposition of dental cotton rolls can modulate periodontal proprioception, Scarpa’s ganglion, and muscular proprioception inputs; cottons are placed, so that the occlusal load is distributed on several teeth, minimizing the effect of incongruous dental contacts.2,15

By comparing the tests carried out with cotton rolls in maximum intercuspation is possible to define the presence of a postural interference of occlusal origin: if the area and the oscillation length of the center of gravity are more extensive in the examination carried out in maximum intercuspation, it can be assumed that postural management is strongly conditioned by dental contact. In this case, the occlusion induces negative alterations in the postural strategies of balance control. A direct correlation between TMDs and postural interference of occlusal origin was found in this study. Proprioceptive information (depending on muscles, tendons, and joints), vestibular, visual, and information from cortical and subcortical motor areas take part in postural control.

In particular, mandibular proprioception is based on pieces of information derived from masticatory muscles and periodontal ligaments: these structures give a contribution in controlling the head posture through the sternocleidomastoid muscle. Any dysfunction of these sensory receptors is compensated by postural strategies in particular by position of the head, neck, and cervical tract.1623

Many studies have shown a functional connection between the motor system of the jaw and the cervical one, which probably allows the trigeminal system to modulate the cervical movements during mastication.13,24,25

Indeed, trigeminal inputs derived from periodontal receptors, TMJ receptors (due to the rotation and/or translation of the condyles), and muscular receptors (due to the variation in the mandibular position) can modulate the neuronal motor of the cervical muscles.26

Eriksson et al. in 1998 suggested that orofacial inputs can influence motor control mechanisms of the head and neck. This could be due to the existing relationship between the descending trigeminal nerve and the dorsal roots of the cervical tract. The neurons of the V cranial nerve and those of the VII, IX, and X cranial nerves share the same neuronal pools of the upper part of the cervical tract.27,28

Balance maintenance is a complex process in which neuronal, muscular, skeletal, visual, and vestibular components are involved. Brain stem and cerebellum centers are activated by pieces of information received from sensory system. An alteration in one body district can induce pain or dysfunction in another, through the activation of the central nervous system. From a pilot study carried out on rats demonstrated a reciprocal influence between dental malocclusion and postural deficits.2931

No significant correlations were found between malocclusion and postural control in this study. However, patients with TMDs have a higher prevalence of cervical and neck muscle activity dysfunctions, which can influence the masticatory muscles. An inadequate position of the head requires an additional strain on the cervical region, altering the entire masticatory.32

Jaw muscles’ activity is associated with that of the neck and trunk muscles. Alterations in muscle balance could influence the mandibular position. On the contrary, changes in the mandibular posture, regardless of whether they are caused by occlusion, muscle disorders, or temporomandibular dysfunctions, can affect the neck muscles and posture.3335

When the patient’s ability to compensate is reduced, he or she is not able to manage the occlusal disharmony and presents TMDs.

According to this, postural aspect plays a key role in the genesis of TMDs. The therapeutic approaches for TMDs vary greatly depending on the different etiological theories. The pathogenesis mechanism of these disorders has not yet been completely clarified. It has been shown that the multidisciplinary approach allows to achieve the best results in pain management.33,36,37

When the compensation capacity is reduced, there is a worsening in balance control strategies which manifest itself in maximum intercuspation more than through cotton rolls interposition.

Ferrario et al. in 1996 highlighted that, although there were no variations in the center of pressure, the center of gravity oscillations were reduced during the cotton roll test in patients with TMDs.15

Temporomandibular disorders patients, compared with healthy patients respond with a greater risk of developing pain on muscle palpation when occlusal interferences are iatrogenically introduced.38

A limitation of this study is the small population analyzed, and also the interpersonal variability such as tolerance to malocclusion or pain in case of TMD could play an important role in the statistical results. This topic has to be deeply analyzed in the future to better understand the complex relationship behind occlusion, postural stability, and TMJ.


The lack of significance in the correlation between TMDs and muscular interference of occlusal origin found in this study is not surprising as said in literature. Indeed, muscular compensations seem not to be related to postural imbalance, but the postural aspect may play a key role in the genesis of TMDs.

A multidisciplinary approach is required for TMDs: therapy with oral splints allows to give greater compliance to the system by acting only on the local aspect of the problem since splints allow muscles to guide the jaw in a position of functional equilibrium by deleting proprioceptive information of the periodontal ligament mechanoceptors.10

Many authors recommend a rehabilitation of the craniomandibular system due to the correlation between posture and TMJ function. The American Academy of Craniomandibular Disorders and the Minnesota Dental Association indicate physiotherapy as an important treatment to decrease musculoskeletal pain, reduce inflammation, and restore the function of the stomatognathic apparatus; and also osteopathy may induce changes in the dynamics of the stomatognathic apparatus, offering a valid support to the clinical approach of TMDs.16,32,39,40

What does this Study Add?

This is the first study to compare with chi-square test the athlete’s occlusion, TMDs, postural balance, and masticatory muscular balance to find statistically significant correlations. We did not detect any significant correlation except between TMDs and postural imbalance, and this can be related to ascending or descending compensations. It is important for athletes to have good occlusal balance, in order to achieve a good postural balance, which could lead to greater results during competitions, prevent injuries, and may also increase the muscular force. Gnathological treatment evaluated through EMG allows to obtain improvements in the occlusal balance.


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