Instant reduction in postural sway during quiet standing by intraoral dental appliance in patients with Whiplash associated Disorders and non-trauma neck pain

Methods of postural analysis in connection with the stomatognathic system. A systematic review

This systematic review aimed to identify the main tools used to analyze the relationship between the postural and stomatognathic systems. The study followed the PRISMA guidelines, and data were collected from Science Direct and PubMed databases to identify articles published until December 2022. After applying inclusion and exclusion criteria, 26 articles were selected from the initial 903 articles. The selected articles were full-text studies in English or Romanian, examining the relationship between dental occlusion and posture, measuring postural parameters using various tools, implementing occlusal changes, evaluating patients with permanent dentition, or analyzing the connection between occlusion and posture in a unidirectional manner. The findings indicate that orthognathic surgery and orthodontic mouthguards can significantly enhance postural balance and athletic performance. In addition, 63% of the studies concluded that varying modifications and occlusal conditions impact posture. Notable differences exist concerning posture and Angle dental occlusion classes, and different occlusal devices used to simulate malocclusion can affect patients' postural systems in response to external stimuli. The stabilometry platform is the predominant method for measuring postural parameters; however, other researchers have employed raster stereography, photogrammetry, mobile phone apps, and the Fukuda-Unterberger test. Consequently, interventions targeting the stomatognathic system should consider potential variations in the postural system.

Effect of static and dynamic jaw positions on postural stability among people with blindness

BACKGROUND

In comparison with the people with normal sight, the mean center of gravity (COG) velocity is significantly higher among blind people. A strong relationship has been shown between jaw and neck sensorimotor and postural control. The purpose of this study was to determine the effect of different static and dynamic jaw positions on postural stability among subjects with blindness.

METHODS

Postural stability was measured as COG velocity in 39 blind subjects under the following five conditions: resting jaw (natural jaw position with no instructions, control), open jaw (teeth of both jaws slightly apart), clenched jaw (teeth tightly closed across each other), chewing (a standard bolus of gum at the natural palace), and tongue position (positioned behind the upper incisors) while standing on firm and foam surfaces.

RESULTS

The mean COG velocity while standing on the firm surface during resting, open jaw position, clenched jaw position, chewing, and tongue positions were 0.54, 0.50, 0.44, 0.59, and 0.46 deg/s, respectively. The mean COG velocity while standing on the foam surface during resting, open jaw position, clenched jaw position, chewing, and tongue positions were 1.42, 1.23, 1.10, 1.14, and 1.06 deg/s, respectively. Compared to the firm surface, the COG velocity was significantly higher on the foam surface in all five conditions (p < .001). In the comparison between the conditions, there were no significant differences in either the firm or foam surface in all five conditions (p > .05).

CONCLUSION

People with blindness behave in the same way as sighted subjects on firm and foam surfaces. However, changes in static and dynamic jaw positions do not affect postural stability among them.

A meta-analysis and systematic review of changes in joint position sense and static standing balance in patients with whiplash-associated disorder

OBJECTIVE

To synthesise and analyse the current evidence regarding changes in joint position sense (JPS) and standing balance in people with whiplash-associated disorder (WAD) taking the presence or absence of dizziness into account.

DATA SOURCES

PubMed, CINAHL Plus, Web of Science, Embase, MEDLINE and APA PsycINFO were searched by two independent reviewers from inception until August 2020 and reference lists of all included studies were also reviewed.

STUDY SELECTION

Only cross-sectional studies that measured JPS and/or standing balance between people with WAD vs. healthy controls (HC) or people with WAD complaining of dizziness (WADD) vs. those not complaining of dizziness (WADND) were selected.

DATA EXTRACTION

Relevant data were extracted using specific checklists and quality assessment was performed using Downs and Black Scale (modified version).

DATA SYNTHESIS

Twenty-six studies were included. For JPS, data were synthesized for absolute error in the primary plane of movement for separate movement directions. For standing balance, data were synthesized for traditional time- and frequency domain sway parameters considering the conditions of eyes open (EO) and eyes closed (EC) separately. For meta-analysis, reduced JPS was observed in people with WAD compared to HC when the head was repositioned to a neutral head position (NHP) from rotation (standardised mean difference [SMD] = 0.43 [95%: 0.24-0.62]) and extension (0.33 [95%CI: 0.08-0.58]) or when the head was moved toward 50° rotation from a NHP (0.50 [0.05-0.96]). Similarly, people with WADD had reduced JPS compared to people with WADND when the head was repositioned to a NHP from rotation (0.52 [0.22-0.82]). Larger sway velocity and amplitude was found in people with WAD compared to HC for both EO (0.62 [0.37-0.88] and 0.78 [0.56-0.99], respectively) and EC (0.69 [0.46-0.91] and 0.80 [0.58-1.02]) conditions.

CONCLUSION

The observed changes of JPS and standing balance confirms deficits in sensorimotor control in people with WAD and especially in those with dizziness.

Influence of different jaw positions on dynamic balance using Y-balance test

BACKGROUND

Jaw sensory-motor system has been shown to affect static balance of the body. It would be interesting to know whether it can influence dynamic balance as well. The objective of this study is to examine the influence of different jaw positions on dynamic balance using the Y-balance test.

METHODS

Eighty healthy male participants aged 20-35 years were invited to participate in this study. Dynamic balance was measured by the Y-balance test in three directions (anterior, posteromedial, and posterolateral) for each leg separately in three jaw positions: resting jaw (control), open-jaw, and clenched jaw.

RESULTS

There were no significant differences in reach distances between the different jaw positions except in the posterolateral direction. In comparison with resting jaw position, reach distance was significantly higher in open-jaw position for the right leg and in clenched and open-jaw positions for the left leg in the posterolateral direction.

CONCLUSIONS

Although various studies have shown direct or indirect influence of jaw sensory-motor system on static postural control, results of this study point to limited relation with dynamic postural control among healthy subjects. However, it supports the potential of the jaw sensory-motor system to affect motor control during functional tasks in patients with postural instability or similar disorders.

Effect of jaw functional status on neck muscle endurance

OBJECTIVE

To investigate the effect of resting jaw and maximum voluntary clenching on neck flexor and extensor muscle endurance.

DESIGN

Neck flexor and extensor endurance was measured in a college health clinic in 85 male college students in two test positions: resting jaw (control) and maximum voluntary clenching.

RESULTS

Mean neck flexor muscle endurance values during resting jaw and maximum voluntary clenching were 70.06 SD 28.24, and 60.03 SD 16.5, seconds respectively. Mean neck extensor muscle endurance values during resting jaw and maximum voluntary clenching were 105.54 SD 29.9, and 98.32 SD 24.54, respectively. Both values were significantly lower while maximum voluntary clenching as compared to resting jaw position (p < 0.05).

CONCLUSION

Modification of jaw position can affect neck muscle endurance. Results of this study further supports sensory-motor relation between jaw and neck region.