Information Value of Functional Status of the Stomatognathic System for Postural Balance Regulation

Mini-review: Pathways of postural disturbances tracing to the stomatognathic system

Postural alignment is strongly shaped by inborn anatomical and nonvolitional neural factors, whereas postural stability is dynamic in nature and driven by both automatic and volitional sensorimotor processes. The sensory and motor systems responsible for these functions are tightly integrated with the central nervous system, several vital structures of which are in close proximity to the stomatognathic system. Interventions in the oral cavity have therefore been stipulated to provide sensory feedback, which may then be translated into motor function. Since the early 90 s, numerous intervention studies have provided evidence of this correlation, with traditional views advocating that causative factors are mainly indirect. Dynamic postural responses were thus predominantly considered manifestations of head displacement, with most studies identifying potential connections along active and passive muscular interactions. The consideration however, that neuromuscular adaptations of whole-body dynamics might extend beyond biomechanical responses and involve direct pathways as well, has led to a recent paradigm shift, challenging conventional perspectives. Among the suggested pathways are central projections of trigeminal afferents, providing inputs for the oculomotor system, as well as active and passive muscular interactions. Further intervention studies indicate a sensory integration of the stomatognathic system to proprioception, likely through neural networks that work in concert with visual cues and the vestibular organs. Building on this accumulating pool of evidence, a timely perspective is provided on a critical yet underexplored aspect of neurophysiology: the intricate interplay between the cranio-cervico-mandibular system and the broader framework of body posture.

The Effect of Asymmetrical Occlusion on Surface Electromyographic Activity in Subjects with a Chewing Side Preference: A Preliminary Study

The relationship between asymmetrical occlusion and surface electromyographic activity (sEMG) in people with different chewing preferences is not clear. In this study, the 5 s sEMG changes in the masseter muscle (MM), sternocleidomastoid (SCM), lateral (LGA), and medial (MGA) gastrocnemius muscles were recorded in controls, and subjects with chewing side preference (CSP) during clench with bilateral (BCR), left (LCR), and right (RCR) posterior teeth placement of cotton rolls. The images of the middle 3 s were selected and expressed as the root mean square (unit: μV/s). The EMG waves of bilateral muscles were compared by computing the percentage overlapping coefficient (POC). Only the POCMM of the CSP showed gender differences at BCR and RCR. Between the control group and the CSP group, there were significant differences in the POCMM and the POCLGA at BCR. In addition, there was a significant difference in POCMM and POCSCM between the two populations in different occlusal positions. The change in the POCSCM correlated with the change in the POCMM (r = 0.415, p = 0.018). The experiment-induced asymmetrical occlusion showed that the altered symmetry of the MM correlated with the altered symmetry of the SCM. Long-term asymmetrical occlusion (i.e., CSP) not only affects MM but also has potential effects on other superficial muscles (e.g., LGA).

Experimental Analysis of the Use of Cranial Electromyography in Athletes and Clinical Implications

Background: Cranial surface electromyography is assumed to analyze the correlation between the stomatognathic apparatus and the muscular system and its implications on the physical status of professional athletes. The purpose of this paper is to evaluate surface cranial electromyography as an aid in the diagnosis and treatment of occlusal and muscular disorders in professional athletes. Methods: A sample of 25 athletes (mean age 23 years, 20 men and 5 women) underwent electromyographic recording; among them, 13 had a sports injury condition (symptomatic athletes), while 12 were in perfect physical condition (asymptomatic athletes). At odontostomatological examination, 6 showed cranio-mandibular disorders (dysfunctional athletes), while 19 showed no disorders (functional athletes). The treatment plan to resolve the symptoms of the dysfunctional athletes was chosen based on the electromyographic data. One month after the start of therapy with an occlusal splint, a follow-up was performed, and the results were compared with the initial data. Results: Statistical analysis showed that the chosen therapy following the use of electromyography was effective in 72% of cases, while 28% of patients did not respond to therapy (p = 0.028). Conclusions: The use of cranial electromyography in competitive athletes is a valuable tool in therapeutic choice aimed at balancing occlusal loads and improving the patient’s global tonic postural attitude, resulting in positive feedback in the qualitative assessment of sports performance.

The Influence of Dental Occlusion on Dynamic Balance and Muscular Tone

Excellent postural control is essential to improve the physical performance of athletes. Stability of the body during motor tasks depends on different physiological systems. The influence of dental occlusion on body balance has been widely investigated in the past few years. It has been suggested that this relationship is strengthened by disturbing environments for balance control (i.e., unstable platform, fatigue, development tasks.). Moreover, dental occlusion may influence the muscle tone of both masticatory and postural muscles, which are involved in the preservation of balance. Therefore, we attempted to determine whether (i) there are differences in dynamic balance assessed by the modified star excursion balance test between opposed dental occlusion conditions (dental contact: intercuspal position/no dental contact: cotton rolls mandibular position) and (ii) dental occlusion influences the biomechanical and viscoelastic properties of the masticatory and postural muscles assessed with MyotonPRO^®. Thirty physically active subjects were recruited for the study. The main findings were the following: (i) the Star Excursion Balance Test composite score was significantly higher for measurements made in cotton rolls mandibular position (p < 0.001) and also in subjects showing a correct occlusion (p = 0.04), and (ii) the biomechanic and viscolelastic properties of selected muscles showed different trend according to the presence of malocclusal traits. It is concluded that dental occlusion conditioned both dynamic stability and the biomechanic and viscoelastic properties of the analyzed muscles.

Efficiency and Prospects of Diagnosis of the Functional State of the Dental System

This paper presents the results of studying the effectiveness of the developed method for diagnosing the functional state of the dental system. The results indicate that the accuracy of the method is about 80%. The results of previous studies are reviewed and the prospects for diagnosis of the functional state of the dental system as a research and practical trend in dentistry are outlined. The physiological regularities of the dental system functioning and relationship between its functional status and the autonomic nervous and postural systems prompt a new trend of research, functional diagnosis in dentistry and interpretation of the findings of functional studies. The prospects of functional diagnosis in dentistry are discussed.