Occlusion and center of foot pressure variation: is there a relationship?

Mandible Position and Chewing Preference Side Do Not Alter Plantar Support in Children Aged 4-11 Years

Introduction

Mandible positioning can cause global postural adaptations. Physiotherapists and dentists try to relate the mandible position and chewing side to plantar support; however, this indication is uncertain.

Objectives

To check the existence of a relationship between mandible position, preferred chewing side, age, and plantar support in children.

Materials and methods

This is a cross-sectional study with 93 children, aged between 4 and 11 years. Photogrammetry was used to confirm the mandibular positions (centralized, to the right, and to the left), and baropodometry was used to measure plantar support. The mandibular displacement distance to the right and left was evaluated, and the plantar support in the three mandibular positions was compared as a function of age (4-7 and 8-11 years) and preferred chewing side.

Results

There was greater mandibular displacement in left laterality [13 (9-19) cm] compared to right laterality [7 (3.50-12.00) cm] (p < 0.01). Mandibular position did not alter mean pressure, maximum pressure, or plantar support surface (p > 0.05). With the mandible centralized, higher mean pressure, maximum pressure, and surface area were observed in the left foot (p < 0.01). Older children showed greater mandibular displacement to the left (p < 0.01). No differences were observed for the variables of plantar support as a function of age (p > 0.05) and chewing side (p > 0.05). There was a moderate to strong correlation between age, body mass, height, and plantar surface area (0.63 < r < 0.83; p < 0.05) and between mean and maximum pressures of plantar support (0.58 < r < 0.89; p < 0.05).

Conclusion

Mandibular position, age, and preferred chewing side do not influence plantar support in children.

How to cite this article

Bittar KCB, Zamboti CL, Macedo CSG. Mandible Position and Chewing Preference Side Do Not Alter Plantar Support in Children Aged 4-11 Years. Int J Clin Pediatr Dent 2024;17(6):658-664.

Influence of the mandibular position on various postural anatomical segments

OBJECTIVE

To determine postural changes in relation to mandibular position in maximum intercuspation and at rest in adult patients of both sexes.

METHODS

: A descriptive observational clinical study was carried out in 76 patients. Using an analyzer and the Meersseman test, the necessary dermal points for postural analysis were located.

RESULTS

: The authors found significant differences in the posture adopted by the patient between maximum intercuspation and mandibular rest in the frontal, sagittal, and dorsal planes. Foot support in the right foot went from cavus to normal in 6% of the sample, and from flat to normal in 2.5% of the sample in the jaw rest position.

CONCLUSION

Postural changes were observed in various segments, with clinical and statistical significance at cervical level in the frontal plane, in the biscapular variable in the dorsal plane, and at the level of the lower limbs in the bipopliteal and bimalleolar variables.

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.

Improvement of cervical spine mobility and stance stability by wearing a custom-made mandibular splint in male recreational athletes

OBJECTIVES

The range of motion (ROM) of the cervical spine and postural stability are important for an economical and motorically adequate adaptation of the body to any situation. Therefore, this study aims to analyze whether these two components of postural and movement control can be influenced by means of a splint in a centric position compared to habitual occlusion.

METHODS

38 recreational male athletes volunteered. Cervical spine ROM was recorded using an ultrasound system and the a pressure measuring plate for postural stability (length of center of pressure (CoP) movement, area of CoP). The two dental occlusion conditions employed were the habitual occlusion and wearing a splint in an idealized, condylar position close to the centric position. Level of significance was set at ρ ≤ 0.05.

RESULTS

The cervical spine mobility increased significantly by wearing the splint regarding rotation to the left (+3.9%) and right (+2.7%) and lateral flexion to the left (+4.4%) and right (+6.7%). Wearing the splint reduced the area of sway deflections by about 31.5% in the bipedal stance and by about 2.4% (left) and 28.2% (right) in the unipedal stance. The CoP trace was reduced in the sagittal plane by approximately 8.2% in the right single-leg stance.

CONCLUSIONS

The major findings seem to demonstrate that wearing a splint that keeps the jaw close to the centric relation may increase the cervical ROM and may improve balance stability in male recreational athletes. Changing the jaw relation in athletes can possibly aid the release of performance potentials by improving coordination skills.

Interaction between posture and maxillomandibular deformity: a systematic review

Maxillomandibular deformity (MMD) and body posture appear to be correlated. However, no systematic literature review of the available evidence to support this correlation has been performed to date. The aim of this study was to conduct a systematic literature review on posture and MMD. This systematic literature review was registered in the PROSPERO database. Systematic searches of the MEDLINE, Scopus, Cochrane Library, and Web of Science databases were performed. In total, 13 clinical studies were included. Nine found a significant association between MMD and body posture or body balance: two studies showed a correlation between increased cervical lordosis and skeletal class III MMD, two studies showed an interaction between mandibular deviation and scoliosis, four studies demonstrated a significant association between lumbar column and pelvis anatomy and MMD, and one study found a correlation between displacement of the centre of mass and MMD. However, the level of evidence is low; the methods used to evaluate body posture and MMD were inconsistent. Orthognathic surgery could modify body posture. Although there seems to be an interaction between body posture and facial deformity, the number of studies is too small and the level of evidence too low to strongly support this association.

Plantar Pressure Variations Induced by Experimental Malocclusion-A Pilot Case Series Study

Background: All body systems involved in ensuring a healthy posture (musculoskeletal system, oculomotor, oto-vestibular and occluso-cranial-mandibular) are essential in maintaining postural balance. Research Question: Does experimental malocclusion in subjects in static position determine variations in plantar pressure? Methods: Overall, 31 subjects were included in the study. The plantar pressure was evaluated in five different points: lateral and medial heel, midfoot, 1st and 5th metatarsal area. Using a specially designed splint, an artificial malocclusion was induced on the right hemimandibular arch. The pressure was measured at 0 (T0), 15 (T1) and 30 min (T2) after splint application. Results: The right external plantar sensors recorded statistically significant differences in pressure values after 15 min of splint wear (5th metatarsal area, p = 0.05; midfoot, p = 0.04). Important pressure values were also recorded by the left internal plantar sensors (1st metatarsal, p = 0.01; medial heel, p = 0.006), after 30 min of splint wear. Conclusions: Asymmetrical experimental malocclusion produces early changes in plantar pressure, a proof of compensatory mechanisms induced by secondary postural imbalance.

Influence of dental occlusion conditions on plantar pressure distribution during standing and walking - A gender perspective

The aim of this study was to investigate gender-specific influences of different symmetric and asymmetric occlusion conditions on postural control during standing and walking. The study involved 59 healthy adult volunteers (41 f/19 m) aged between 22 and 53 years (30.2 ± 6.3 years). Postural control measurements were carried out using a pressure plate by measuring plantar pressure distribution during standing and walking test conditions. Seven different occlusion conditions were tested. Prior to a MANOVA model analysis, the relationship between the two test conditions were checked using a factor analysis with a varying number of factors (between 2 and 10). The plantar pressure distributions during walking and standing are independent test conditions. The coefficient of variance across all variables between the conditions and genders was not significant: t(46) = 1.51 (p = 0.13). No statement can be made whether, or not, the influence of gender is greater than the influence of the conditions. Healthy male and female test subjects did not show any difference between seven occlusion conditions on the plantar pressure distribution while standing or walking. No differences between the genders were found for any of the investigated variables. In contrast to custom-made occlusion splints, simple cotton rolls appear not to influence the neuromuscular system in a systematic manner.

Dental Malocclusion and Its Relation to the Podal System

Background and Objective: This study analyzes the possibility that Stomatognathic and Postural systems are related by muscle chains. Malocclusion may influence the posture, contact between the foot and the ground, center of mass, footprint or vice-versa. This study aimed to verify whether there is a relationship between dental occlusion and podal system. Materials and Methods: A cross-cutting, descriptive study was carried out on 409 children (222 boys and 187 girls) between 8 and 14 years old. Dental occlusion was assessed on the sagittal plane (Angle's classification) the contact between the foot and the ground and the center of mass were evaluated using a stabilometric platform. Results: There was a statistically significant relationship between the plantigrade phase, the contact surface area and center of gravity. There was a prevalence of molar and canine Angle's class II malocclusion. In molar class II, an anterior center of gravity was predominant, in class I it was centered and in class III, it was posterior. There was significant correlation between malocclusions and the FPI (foot posture index) of the left foot and the height of the scaphoid in the right foot (P < 0.001). Conclusions: Some authors agree with our results. There is still much uncertainty in terms of showing a relationship between both systems. In addition, there is scarce scientific evidence on the topic. Some kind of relationship between the two systems has been proven. Studies that evaluate a group of subjects in a longitudinal manner are necessary to enable the changes taking place in both systems to be defined.

Influence of Dental Malocclusion on Body Posture and Foot Posture in Children: A Cross-Sectional Study

The number of studies that investigate the correlations between the temporomandibular system and body posture, postural control, or the distribution of plantar pressure has recently been increasing. However, most of the existing information is not conclusive. Therefore, the study objective was to evaluate if the features of dental malocclusion are correlated with body posture alterations at the lower limb level. This is a multicentre cross-sectional study with 289 children (8-14 years). Angle's molar relation was analysed at the dental level. The postural control and the plantar pressure distribution were recorded via a force platform. Correlation and inferential analysis between the Angle class and the foot's biomechanics were tested. The centre of gravity is anteriorised in Angle's Class II in both the molar class (p ≤ 0.001) and the canine class (p ≤ 0.001). Likewise, a relationship was observed between the contact surface and Angle's classes, being higher in class III than in II (p ≤ 0.001). The plantigrade phase is shortened in Angle's Class III. A relationship was found between Angle's Class II and a forward movement of the centre of gravity. No relationship was found between the Foot Posture Index and the truncated scaphoid height and the dental classification. An evident relationship between the gait typology and dental malocclusion was not found.

Systematic changes of the static upper body posture with a symmetric occlusion condition

Background

Temporary occlusal changes and their influence on the upper body statics are still controversially discussed. Furthermore, concrete statements on whether age- or gender-specific differences in neurophysiological reactions exist are missing. Therefore, it is the aim of this study to evaluate the immediate effects of a symmetrical occlusion blocking on the upper body posture. These effects shall be investigated for both genders and for a larger age range.

Methods

In this study, 800 (407f/393 m) subjects volunteered aged from 21 to 60 years. Both genders were divided into four age groups according to decades. The three-dimensional upper body posture was measured by using the rasterstereography (ABW-Bodymapper). The habitual static posture was measured in two dental occlusion conditions (a) in rest position and (b) symmetrical blocking in the bicuspid region by cotton rolls.

Results

A significant reduction of the trunk length (0.72 mm; p <  0.001), an increase of the lumbar (0.30°; p <  0.001) and the thoracic bending angle (0.14°; p = 0.001), a reduction of the spinal forward decline (0.16°; p <  0.001) and a reduction of the scapular distance (0.36 mm; p = 0.001) was found. Gender-specific reactions can only be recorded in scapular distance, in that regard men reduce this distance while over all age groups women did not show a significant change.

Discussion

Slight gender- and age-independent reactions due to a symmetric occlusion blockade are shown: A gender independent reaction of the spinal related variables in the sagittal plane (thoracic and lumbar flexion angle, trunk length, spinal forward decline). In addition, a gender specific change of the shoulder blade distance could be observed, where men reduced the distance while female did not show a change. However, since these reactions are of a minimum amount, it can be concluded that neurophysiological compensation mechanisms work equally well regardless of age and sex, and the upper body posture of healthy people changes only very slightly due to a temporarily symmetrical altered bite position.

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.

A kinematic analysis on the immediate effects of occlusal splints in gait and running body sway patterns

Objective: This study aims to determine whether changes in dental occlusion are correlated to body posture during walking and running.Methods: Fifteen healthy subjects were assessed by a prosthodontist and deemed asymptomatic. Analyses of gait and running were performed in three conditions, in random order: a) occlusal splint; b) placebo splint; and c) no splint. The occlusal splint used in this study positioned the mandible in a stable position. Kinematic data was collected using a 3D motion capture system.Results: Changes in dental occlusion induced by occlusal splints did not influence body sway during gait or running. No significant differences were found between any of the test conditions.Conclusion: Occlusal splints have no effect on body sway during gait or running. High inter-subject variability in kinematic parameters was found, which should be considered in future studies.

Association between constitution, medical history, axiography and postural control in women aged between 21 to 30 years

The aim of this study was to determine association between constitutional, medical history and axiographic parameters with postural control parameters. Overall, 106 healthy female subjects aged between 21 and 30 years were measured. Data collection was carried out by completing a questionnaire on constitutional parameters, illnesses, accidents and medical/orthodontic therapies, as well as by axio- and posturographic measurements. Data were analyzed using correlations, pair comparisons and group comparisons. The significance level was set at p ≤ 0.05. The statistical evaluation showed significant correlations between sporting exercise and body sway in the sagittal direction (p ≤ 0.03), the BMI and the load on the forefoot/rear foot (p ≤ 0.01), the mouth opening and the load on the forefoot/rearfoot (p ≤ 0.01) and the presence of a deviation with the load on the left/right foot (p ≤ 0.01). The physical condition as well as the temporo-mandibular system are associated with the postural control in young women. Therefore, a holistic diagnosis and therapy will be supported by the present outcomes.

The Effect of Clenching and Occlusal Instability on Body Weight Distribution, Assessed by a Postural Platform

The purpose of this research project was to investigate whether or not clenching and occlusal instability of Angle's Class I malocclusion have an effect on body weight distribution in healthy adult subjects. Twenty adults (fourteen males and six females, ages 27-40, mean age 31.7 years, SD 3.32) were included in this study. The MatScan (Tekscan Inc., Boston, MA) system was used to measure the body weight distribution changes of the subjects. Four body weight distribution measurements were taken for each subject while (1) the mandible was in the rest position (no tooth contact) (RES), (2) subject was clenching (maximum intercuspation of the teeth with heavy occlusal forces) (CL), (3) subject was clenching on the right side (with 1 mm disocclusion on the left side) (CLR), and (4) subject was clenching on the left side (with 1 mm disocclusion on the right side) (CLL). The lateral and the anteroposterior body weight distribution changes during the different clenching conditions (both sides, right, and left) were compared to those at which the mandible was at the rest position. The statistical significance of these results was tested with a Chi-Squared test (p<0.05). Based on the findings of the present study it was concluded that clenching and occlusal instability are associated with lateral body weight distribution changes.

Sensorial Afferents, Expectations, and Craniocervical Postural Relations in Adults who are Blind and Sighted

In this study, the neck and head relative to the ground were more flexed, while the head relative to the neck was more extended, in the subjects who were blind than in the sighted subjects. The introduction of external (sound) or proprioceptive (mandibular position, look ahead) inputs modified craniocervical posture and relationships (extension) in both groups.

Sensorial Afferents and Center of Foot Pressure in Blind and Sighted Adults

Variations in body posture were evaluated in 19 blind and 19 sighted adults by changes in the subjects’ center of foot pressure on a force plate in time in three positions. The subjects who were blind had significantly larger body sway than did the sighted subjects in all trials except those in the sound position, where they had a better control of their stance than did the sighted subjects, and their body oscillations were also reduced in the forward-looking position. Thus, sound or proprioceptive adjunctive inputs can significantly alter body sway in adults who are blind.

Analysis of Dental Malocclusion and Neuromotor Control in Young Healthy Subjects through New Evaluation Tools

The presence of a correlation between stomatognathic and postural systems has been investigated by different authors trying to identify a possible influence of dental occlusion on body posture and balance. The aim of this study was to evaluate the relationship between dental occlusion and neuromuscular control in a healthy young population using modern evaluation tools. 25 subjects (9 males and 16 females, aged 23 to 44) were evaluated for dental occlusion, particularly in relation to overjet and overbite parameters, anterior and posterior crossbite, scissor bite, mandibular crowding, molar and canine class, and deviation of the median dental line. Neuromotor control was assessed using two different types of stabilometric platforms in both monopodalic and bipodalic equilibriums (Prokin-B and MF-Stability, Tecnobody, Italy). All subjects were evaluated with and without cotton rolls positioned between the upper and lower arches at the premolar level in order to temporarily eliminate any pathological contact. In all 25 subjects, no statistically significant differences were revealed between the evaluations performed with and without cotton rolls in all the analyzed conditions (in static, in dynamics, with open and closed eyes). This study did not find a significant correlation between dental occlusion and neuromuscular control in a young and healthy population.

Impact of orthognathic surgery on the body posture

BACKGROUND

Postural control is classically described as being based on the visual, vestibular, and proprioceptive musculo-articular sensory systems. The influence of mandibular proprioception on postural stabilization remains controversial. Most previous studies analyzed how postural stability is influenced by partial changes in mandibular proprioception (dental occlusion and jaw position).

RESEARCH QUESTION

In the present experiment, we asked whether drastic mandibular changes, resulting from orthognathic surgery (including dental, joint and muscular efferents), modify postural control.

METHODS

The analyzes were performed in 22 patients tested before, and 2.5 months, after orthognathic surgery for treatment of dysmorphic jaws. Experiments were performed under 4 experimental conditions: 2 visual conditions: Eyes Open (EO) and Eyes Closed (EC), and 2 occlusal conditions: Occlusion (OC: mandible positioned by the contact of the teeth), and Rest Position (RP: mandible positioned by the muscles without tooth contact). The analyses focused on head orientation in the frontal plane and on postural stabilization in a static task, consisting of standing upright.

RESULTS

The results show that, 2.5 months after orthognathic surgery, head orientation in the frontal plane was improved, since patient's external intercanthal lines became closer to the true horizontal line when they were tested EC and in OC condition. Postural responses, based on the wavelet transformation data, highlight an improvement in maintaining an upright stance for all the tested sensory conditions. However, such improvement was greater in the EC and RP conditions.

SIGNIFICANCE

These results show, for the first time, that after drastic mandibular changes, the weight of proprioceptive cues linked to the mandibular system may be so enhanced that it may constitute a new reference frame to orient the head in space, in darkness, and improve static postural stabilization, even in the presence of visual cues.

Does occlusal splint affect posture? A randomized controlled trial

OBJECTIVE

The aim of this study was to evaluate the effect of an occlusal splint on body posture of intra-articular temporomandibular joint (TMJ) disorders patients.

METHODS

The study was performed on 45 women affected by TMJ disorders divided into an occlusal splint group and a control group. Rasterstereographic recordings were performed at baseline and after 1, 3, and 6 months, in order to analyze the following postural parameters: trunk inclination, cervical and lumbar arrows, kyphotic and lordotic angles, trunk imbalance, pelvic tilt and torsion.

RESULTS

Regarding the postural parameters in the intragroup analysis, no significant differences were detected. The analysis between the two groups revealed significant differences concerning the cervical arrow, the kyphotic and lordotic angles.

DISCUSSION

Even if some differences were found between the control and the occlusal splint group, the low range of statistical significance made these results not significant from a clinical point of view.

Effects of Dental Occlusion on Body Sway, Upper Body Muscle Activity and Shooting Performance in Pistol Shooters

Occlusal splints, to some extent, have been related to reduced body sway in a static position and increased muscle activity in the upper limbs. However, how dental occlusion status affects sports performance remains unclear. Here, we investigated whether occlusal splints that reposition the temporomandibular joint (TMJ) influenced body posture, muscle activity, and performance in 10-meter pistol shooters. Thirteen national-level male shooters (age = 38.8 ± 10.9 yrs) were recruited for this study, and cleared of any cervical pathology. An occlusal splint (OS) and a placebo splint (PS) were fabricated for each of the subjects, with the mandibular and maxillary position verified by an expert dentist, with the aid of an adjustable articulator. Surface electromyography (EMG) was assessed in the upper limb that holds the pistol while the subjects were standing on a force platform. Subjects performed two series of 10 shots for each of the three experimental conditions (OS, PS, N (no splint)) in randomized order, with the mandible in a rest position. Results revealed similar centre of pressure (COP) parameters in all conditions, despite a reduction in the average oscillation area caused by the OS. There were also no significant differences in EMG activity between conditions in the five upper limb muscles monitored. Consistent with this, shooting performance was similar in all conditions, despite a reduction in shot dispersion in subjects using OS. Thus, changes in dental occlusion status induced by OS do not affect body posture, upper limb EMG muscle activity, or shot performance in healthy male pistol shooters.

Relationship between foot posture and dental malocclusions in children aged 6 to 9 years: A cross-sectional study

The aim of this study was to determine the association, if any, between foot posture and dental malocclusions in the anteroposterior plane, in children.The study population consisted of 189 children (95 boys and 94 girls) aged 6 to 9 years. In every case, previous informed consent was requested and obtained from the parent/guardian and the study was approved by the Ethics Committee of the University of Málaga (CEUMA 26/2015H).This observational, descriptive, cross-sectional analysis is based on a study population (STROBE). Qualified personnel conducted a podiatric and dental examination of each child, recording the Clarke angle and the foot posture index (FPI) as an outcomes measure in the feet, and also dental malocclusions, according to Angle classification.A significant correlation was observed for the FPI scores (for right foot) as well as the Clarke angle (for right foot), in relation to dental malocclusions as determined by Angle classification (P < .001). Of all the supinated feet analyzed, 38.46% were Class II according to Angle classification, and none were Class III. Of the pronated feet, 48.57% were Class III, 42.85% were Class I, and 8.57% were Class II.The Clarke angle decreases with the progression from Class I to III, whereas the FPI increases with that from Class I to III. These findings suggest there is a relation between the Clarke angle and FPI, on the one hand, and dental malocclusion on the other.

Can different occlusal positions instantaneously impact spine and body posture? : A pilot study using rasterstereography for a three-dimensional evaluation

PURPOSE

Orthodontists influence dental occlusion directly. To suggest any link between dental occlusion and body posture is highly contentious, as evidenced by the literature. Rasterstereography, an optical technique that enables three-dimensional (3D) body measurements to be collected, has not yet been used to impartially examine whether different occlusal positions could instantaneously alter spine and body posture. We therefore set out to use this technique to nonsubjectively evaluate this question under static conditions.

METHODS

Optical body scans were collected for 44 subjects, using the Diers formetric 4D system, for seven different mandible positions. In total, ten spinal and body posture parameters were assessed (trunk inclination, trunk imbalance, pelvic tilt, pelvic torsion, fleche cervicale, fleche lombaire, kyphotic angle, lordotic angle, surface rotation, and lateral deviation) for each mandible position and compared with scans performed with habitual intercuspation (HIC).

RESULTS

Significant body posture deviations were found for the fleche cervicale (position of the mandible: right eccentrically), fleche lombaire (positions of the mandible: physiologic rest position, cotton rolls on both sides, bite elevation 1 mm), and the kyphotic angle (positions of the mandible: cotton rolls on both sides, right eccentrically). No other significant differences were detected.

CONCLUSIONS

Data for the parameters that varied with different dental occlusions generated high standard deviations. Therefore, within the limitations of this pilot study, we could not conclusively associate dental occlusion to an instantaneous impact on the tested parameters. The posture changes that we detected could also have arisen from individual neuromuscular compensation; a possibility that must now be ruled-in, or out, by further research studies with a higher number of subjects.

Short-Term Repeatability of Stabilometric Assessments

The authors evaluated the short-term (within-day, between-days) repeatability of center of pressure (COP) displacements. COP sway area and speed were obtained in the morning and afternoon of two separate days, both with open (EO) and closed (EC) eyes, in 10 healthy adults. Agreement and variability among conditions were tested by ANOVA and Bland-Altman plots. Mode (EO/EC, area: p = .032; speed: p < .004), and day (day1/day2, area: p = .006; speed: p = .02) showed significant differences. The EC condition and the second test day showed the largest values, with medium-large effect sizes. Time-of-day did not influence COP displacements. Speed had better agreement than area (Bland-Altman plots). COP displacements were well reproducible within-day, but had significant between-days variations. COP assessments should be performed in the same session.

The effect of denture installation at mandibular rest position on unsteady motion of the centre of pressure in postural sway

Wearing dentures has been believed to decrease the instability of the postural sway using the total length of centre of pressure (CoP) trajectory or the magnitude of its variability. However, the physical aspects of the postural sway have not been taken into account while evaluating the CoP in patients who wear dentures. The CoP fluctuations are found to show a random walk process. Therefore, changes in the random movement of CoP caused by wearing dentures should be examined by nonlinear dynamics that enables analysis of the characteristics found in the random movement. We evaluated the effect of complete denture installation on CoP sway for twenty-six edentulous patients by performing the following steps. First, we excluded subjects who did not show crossover in spectral analyses. Then, we evaluated the spectral characteristics and phase shifts of the velocities of CoP sway for the subjects who showed crossover. We found that wearing complete dentures decreased the fluctuations in the high-frequency part of the power spectral density (PSD) and the phase shift in the mediolateral direction. On the other hand, we also found that the use of complete dentures decreased the fluctuations of PSD amplitude in the anteroposterior direction. From the point of view of the kinetic energy of the musculoskeletal system, we suggested that the use of complete dentures could reduce the energy consumption for the standing posture.

Effect of Jaw Clenching on Balance Recovery: Dynamic Stability and Lower Extremity Joint Kinematics after Forward Loss of Balance

Postural control is crucial for most tasks of daily living, delineating postural orientation and balance, with its main goal of fall prevention. Nevertheless, falls are common events, and have been associated with deficits in muscle strength and dynamic postural stability. Recent studies reported on improvements in rate of force development and static postural control evoked by jaw clenching activities, potentially induced by facilitation of human motor system excitability. However, there are no studies describing the effects on dynamic stability. The present study, therefore, aimed to investigate the effects of submaximum jaw clenching on recovery behavior from forward loss of balance. Participants were 12 healthy young adults, who were instructed to recover balance from a simulated forward fall by taking a single step while either biting at a submaximum force or keeping the mandible at rest. Bite forces were measured by means of hydrostatic splints, whereas a 3D motion capture system was used to analyze spatiotemporal parameters and joint angles, respectively. Additionally, dynamic stability was quantified by the extrapolated CoM concept, designed to determine postural stability in dynamic situations. Paired t-tests revealed that submaximum biting did not significantly influence recovery behavior with respect to any variable under investigation. Therefore, reductions in postural sway evoked by submaximum biting are obviously not transferable to balance recovery as it was assessed in the present study. It is suggested that these contradictions are the result of different motor demands associated with the abovementioned tasks. Furthermore, floor effects and the sample size might be discussed as potential reasons for the absence of significances. Notwithstanding this, the present study also revealed that bite forces under both conditions significantly increased from subjects’ release to touchdown of the recovery limb. Clenching the jaw, hence, seems to be part of a common physiological repertoire used to improve motor performance.

Influence of the Lower Jaw Position on the Running Pattern

Introduction

The effects of manipulated dental occlusion on body posture has been investigated quite often and discussed controversially in the literature. Far less attention has been paid to the influence of dental occlusion position on human movement. If human movement was analysed, it was mostly while walking and not while running. This study was therefore designed to identify the effect of lower jaw positions on running behaviour according to different dental occlusion positions.

Methods

Twenty healthy young recreational runners (mean age = 33.9±5.8 years) participated in this study. Kinematic data were collected using an eight-camera Vicon motion capture system (VICON Motion Systems, Oxford, UK). Subjects were consecutively prepared with four different dental occlusion conditions in random order and performed five running trials per test condition on a level walkway with their preferred running shoes. Vector based pattern recognition methods, in particular cluster analysis and support vector machines (SVM) were used for movement pattern identification.

Results

Subjects exhibited unique movement patterns leading to 18 clusters for the 20 subjects. No overall classification of the splint condition could be observed. Within individual subjects different running patterns could be identified for the four splint conditions. The splint conditions lead to a more symmetrical running pattern than the control condition.

Discussion

The influence of an occlusal splint on running pattern can be confirmed in this study. Wearing a splint increases the symmetry of the running pattern. A more symmetrical running pattern might help to reduce the risk of injuries or help in performance. The change of the movement pattern between the neutral condition and any of the three splint conditions was significant within subjects but not across subjects. Therefore the dental splint has a measureable influence on the running pattern of subjects, however subjects individuality has to be considered when choosing the optimal splint condition for a specific subject.

One-leg standing time with eyes open: comparison between the mouth-opened and mouth-closed conditions

OBJECTIVE

Many studies report a significant relationship between the one-leg standing time with the eyes open and the occlusal relationship. To determine the association between proprioception (the periodontal membrane vs muscle spindle) to the one-leg standing time, the authors compared the one-leg standing time with eyes open between mouth-opened and mouth-closed conditions.

METHODS

The study participants were 107 healthy, elderly patients. The authors measured the one-leg standing time with eyes open between mouth-opened and mouth-closed conditions.

RESULTS

The one-leg standing time was significantly shorter with the mouth opened (21·1±19·1 seconds) than with the mouth closed (25·1±21·4 seconds). Patients whose one-leg standing time was equal or shorter with the mouth opened than with the mouth closed were not different from the other patients with regard to age, handgrip strength, BMI, and the number of remaining teeth.

DISCUSSION

The vertical mandibular position may affect body balance.

Interference of Different Types of Mastication on Static Balance in Individuals without Temporomandibular Disorder

PURPOSE

This study was to determine whether non-habitual (isotonic) bilateral and unilateral mastication with eyes open and eyes closed exerts an influence on static balance in individuals without temporomandibular disorder (TMD).

METHOD

An observational, cross-sectional study was conducted involving 20 volunteers aged 20 to 40 years without temporomandibular disorder. Static balance was assessed with the individuals in a quiet standing position on a force plate performing different types of mastication under six separate conditions.

RESULTS

Significant differences (p < .05) were found in the area of oscillation during bilateral mastication (eyes open) and the right unilateral mastication, significant differences were only found for oscillation area with eyes open and mediolateral center of pressure with eyes closed (p < .05).

CONCLUSIONS

The findings of the present study reveal that the stomatognathic system (bilateral and unilateral mastication) promote changes in some variables of static balance.

Effect of mandibular mobilization on electromyographic signals in muscles of mastication and static balance in individuals with temporomandibular disorder: study protocol for a randomized controlled trial

BACKGROUND

The stomatognathic system and dysfunction in this system may be related to postural control. The proposal of the present study is to assess the effect of mandibular mobilization in individuals with temporomandibular disorder using surface electromyography of the muscles of mastication and stabilometric variables.

METHODS/DESIGN

A randomized, controlled, blind, clinical trial will be carried out, with the participants divided into three groups: 1) facial massage therapy (control group), 2) nonspecific mandibular mobilization and 3) specific mandibular mobilization. All groups will be assessed before and after treatment using the Research Diagnostic Criteria for Temporomandibular Disorders, surface electromyography of the masseter and temporal muscles and stabilometry. This study is registered with the Brazilian Registry of Clinical Trials (RBR9x8ssz).

DISCUSSION

A large number of studies have employed surface electromyography to investigate the function/dysfunction of the muscles of mastication and associations with signs and symptoms of temporomandibular disorders. However, it has not yet been determined whether stabilometric variables offer adequate reliability in patients with this disorder. The results of the proposed study will help determine whether specific and/or nonspecific mandibular mobilization exerts an effect on the muscles of mastication and postural control. Moreover, if an effect is detected, the methodology defined in the proposed study will allow identifying whether the effect is local (found only in the muscles of mastication), global (found only in postural control) or generalized.

The neuromuscular approach towards interdisciplinary cooperation in medicine

BACKGROUND

The contemporary approach of dentistry towards interdisciplinary cooperation is based on the neuromuscular concept. In recent years many authors have pointed out a correlation between orthopaedic and dental findings. Furthermore, there is an intimate biomechanical interrelationship of occlusion with cerebral fluid circulation, left and right equilibrium, gaze stabilisation and headache. The influence of a dental occlusion and temporomandibular joint (TMJ) status on general health has been widely analysed in the current scientific literature.

AIM

The aim of this analytic study was to display the deep relationship between dentistry and other fields of medicine, and to show the necessity of wide cooperation between dentists and physicians.

CONCLUSIONS

This study was based on a review of 41 sources, including specialised articles and books. The significance of different anatomical and physiological preconditions (occlusion, muscles and TMJ status) was considered and evaluated separately. However, as a result of modern concepts of general body health, extending cooperation between different fields of medicine is essential. The practical application of the principles of neuromuscular dentistry enables one to increase greatly the treatment efficiency of aches in muscles, headaches, postural dysfunctions as well as of many other diseases. However, the dentist's contribution to the development of an interdisciplinary approach is underestimated. Many theoretical aspects of the interdisciplinary relationship have not been sufficiently examined, hence the practical consequences remain unclear. Further research in the field is urgently needed.

The diagnostic potential of static body-sway recording in orthodontics: a systematic review

Conflicting data have been reported in dentistry regarding the diagnostic potential of monitoring body sway while in a static standing bipedalic position. This systematic review reappraises previously reported effects of mandibular position, asymmetric occlusion, and temporomandibular disorders (TMDs) on body sway to determine whether there is sufficient evidence for such correlations and to define the potential diagnostic applications in orthodontics. A literature survey was performed using the Medline, LILACS, and SciELO databases, and the Cochrane Library, covering the period from January 1980 to December 2011. Twelve articles qualified for the final analysis. All of these studies investigated the effects of mandibular position, two focussed also on asymmetrical occlusion, and three on TMDs. Only two studies were judged to be of medium or medium/high quality, with all of the rest classified as low-quality design; no study included follow-up. According to the conclusions of these reports, four studies saw significant correlations between body sway and mandibular position or TMDs. After a reappraisal of the full data set, generally no clinically relevant correlations were uncovered in the comparisons. While more investigations with improved levels of scientific evidence are needed, according to current evidence, the static monitoring of body sway as a diagnostic aid in orthodontics may not be indicated.

An evaluation of horizontal jaw relations during standing and sitting with open or closed eyes

When determining the horizontal jaw relation and mandibular movements, a question arises as to the appropriate choice of registration positions. The current study was carried out using 22 adults with full dentition who did not have any discomfort in their skeletal and craniomandibular systems. Occlusion and mandibular movements were investigated with open and closed eyes in standing and sitting positions using an electronic, central-bearing tracing device. The coordinates of the measured parameters are presented using a two-dimensional computer vector diagram. The non-parametric Friedman test was used for statistical data analysis. The measured data obtained for the initial habitual centric relation record (HR), centric relation record (CR), final habitual centric relation record (HR), and protrusion (P) did not significantly differ in the sitting and standing positions or with opened and closed eyes (p = 1.00). With closed eyes, the differences in the average values between the two condylar positions (initial HR/final HR, initial HR/CR, and final HR/CR) decreased in a manner that was independent of the registration position. The CR that was measured in a sitting position with closed eyes was 2.26 mm more retrusive than that measured with open eyes. Before and after CR measurements, only laterotrusion showed significant differences (p=0.02) in patients who were standing with closed eyes. It was concluded that the registration position and visual system could individually influence the measurements of condylar position and mandibular movements. From a clinical perspective, these measurements exhibited the smallest differences when they were conducted with patients in a sitting position with closed eyes.

The Stomatognathic System's Role in the Postural Stabilization in Subjects Suffering from Whiplash Injury Part 1: Patients with Physiological Occlusion

Aim of this study is analyze the effects of dental occlusion on postural stability in patients with previous whiplash and normal occlusion. Materials and methods: 36 adult patients with previous whiplash and normal occlusion (good alignment, 1st class or mild 2nd class deep bite for mandibular retrusion) were selected. The patients were suffering from masticatory muscles pain caused by clenching during sleep. Exclusion criteria: use of psych drugs. To simulate the conditions of sleep (with a reduction of proprio-and esteroceptive inputs for postural management performed by CNS), we used postural Romberg analysis (feet together, closed eyes)on stabilometric platform changing occlusal parameters only, under the following conditions: 1) in occlusal rest position, 2) in centric occlusion, 3) in clenching, 4) with occlusal disengage with cotton rolls and 5) in clenching on cotton rolls. Time of each test: 15 seconds. It was performed a statistical analysis with T-test comparing between them the mean of all tests. Results: stabilometry data (postural ball and ellipse) show better postural performances in centric occlusion and clenching in centric occlusion, and a worsening in all tests with occlusal disengage (with statistically significant difference - p<0.05). Conclusions: postural instability caused by whiplash increases muscles tone and dental clenching as compensatory effects, with onset of facial pain. An occlusal disengage (like an occlusal splint to reduce clenching)induces a postural worsening in patients with normal occlusion, while centricocclusion increases the stability. These results suggest that stomatognathic organ has a new physiological function: the posture stabilization.

The Stomatognathic System's Role in the Postural Stabilization in Subjects Suffering from Whiplash Injury. Part 2: Patients with Malocclusion

Aim of this study is analyze the effects of dental occlusion on postural stability in patients with previous whiplash and malocclusion. Materials and methods: 30 adult patients with previous whiplash and malocclusion (crossbite, mandibular shift, bad alignment, edentulous spaces) were selected. The patients were suffering from masticatory muscles pain caused by clenching during sleep. Exclusion criteria: use of psych drugs. To simulate the conditions of sleep (with a reduction of proprio- and esteroceptive inputs for postural management performed by CNS), we used postural Romberg analysis (feet together, closed eyes) on stabilometric platform changing occlusal parameters only, under the following conditions: 1) in occlusal rest position, 2) in centric occlusion, 3) in clenching, 4) with occlusal disengage with cotton rolls and 5) in clenching on cotton rolls. Time of each test: 15 seconds. It was performed a statistical analysis with T-test comparing between them the mean of all tests. Results: stabilometry data (postural ball and ellipse) show better postural with occlusal disengage (in centric and in clenching), and a worsening in all tests with centric occlusion (with statistically significant difference - p<0.05). Conclusions: postural instability caused by whiplash increases muscles tone and dental clenching as compensatory effects, with onset of facial pain and a worsening of TMJ health in subjects with malocclusion. An occlusal disengage (like an occlusal splint to reduce clenching) induces better postural performances. Sostomatognathic system becomes a source of postural dysfunction and a cause of postural worsening.

Dental occlusion, body posture and temporomandibular disorders: where we are now and where we are heading for

The aim of this investigation was to perform a review of the literature dealing with the issue of relationships between dental occlusion, body posture and temporomandibular disorders (TMD). A search of the available literature was performed to determine what the current evidence is regarding: (i) The physiology of the dental occlusion-body posture relationship, (ii) The relationship of these two topics with TMD and (iii) The validity of the available clinical and instrumental devices (surface electromyography, kinesiography and postural platforms) to measure the dental occlusion-body posture-TMD relationship. The available posturographic techniques and devices have not consistently found any association between body posture and dental occlusion. This outcome is most likely due to the many compensation mechanisms occurring within the neuromuscular system regulating body balance. Furthermore, the literature shows that TMD are not often related to specific occlusal conditions, and they also do not have any detectable relationships with head and body posture. The use of clinical and instrumental approaches for assessing body posture is not supported by the wide majority of the literature, mainly because of wide variations in the measurable variables of posture. In conclusion, there is no evidence for the existence of a predictable relationship between occlusal and postural features, and it is clear that the presence of TMD pain is not related with the existence of measurable occluso-postural abnormalities. Therefore, the use instruments and techniques aiming to measure purported occlusal, electromyographic, kinesiographic or posturographic abnormalities cannot be justified in the evidence-based TMD practice.

[Dento-facial orthopedics and osteopathy]

Osteopathy has grown rapidly. Given their common action on children and adolescents, the collaboration between dentofacial orthopedics and osteopathy is increasingly common. It therefore becomes necessary and urgent to investigate whether, based on data acquired from science, there is evidence of possible interrelations between the two disciplines. After reviewing the literature, very few scientific publications demonstrate the utility of osteopathy and its relationships with other disciplines. However, the relationship between occlusion and posture seem relatively proven, especially in the sagittal direction. On the other hand, although the mobility of the cranial bones is established, the primary respiratory motion is still subject to controversy, even among osteopaths. This, even as orthodontics has long been accused of countering the primary respiratory motion of cranial bones (PRM). Today osteopaths do not reject orthodontics anymore, because the return to a physiological bite situation is considered beneficial. According to expert opinion (without proof, however), some orthodontic devices (like headgears) which block the sutures are still to be avoided and require appropriate monitoring osteopathy. The controversy over the adverse effects of orthodontic treatment is becoming more nuanced by osteopaths, and modern orthodontics claiming a «global» approach of patient, collaboration may be possible in future year.

Do malocclusion and Helkimo Index ≥ 5 correlate with body posture?

Whether there are correlations between the stomatognathic system and body posture remains controversial. Here, we have investigated whether malocclusal traits and having a Helkimo Index ≥ 5 show detectable correlations with body-posture alterations in children and young adults. A total of 1178 11- to 19-year-old subjects were divided into four groups: (i) controls; (ii) malocclusion; (iii) Helkimo Index ≥ 5 and (iv) malocclusion + Helkimo Index ≥ 5. Dental occlusion assessment included the following: overbite, overjet, posterior crossbite, scissorbite, mandibular crowding and dental class. Subsequently, body-posture assessments were performed through static analyses of body inclination and trunk asymmetry, and according to the dynamic Fukuda stepping test. Univariate and multivariate statistical analyses were performed. Although at the univariate level both the trunk asymmetry and Fukuda stepping test showed significant differences among the groups, the multivariate level revealed that age and gender were mostly responsible for this. The only significant correlation that was seen was for the malocclusion + Helkimo Index ≥ 5 group: these subjects had a positive (worse) trunk asymmetry and a negative (better) Fukuda stepping test performance. At the further multivariate analyses of each single malocclusal trait ⁄Helkimo Index ≥ 5 (irrespective of the groups), only an increased overbite showed a statistically significant association with a slightly better Fukuda stepping test performance. Given the small number of significant associations seen and their limited entities, this study does not support the existence of clinically relevant correlations for malocclusal traits and Helkimo Index ≥ 5 with body posture in children and young adults.

Interrelationships between dental occlusion and plantar arch

OBJECTIVE

The aim of this study was to evaluate the influence of different jaw relationships on the plantar arch during gait.

METHODS

168 subjects, participating in this study, were distributed into two groups: a control (32 males and 52 females, ranging from 18 to 36 years of age) and a Temporomandibular joint disorders group (28 males and 56 females, ranging from 19 to 42 years of age). Five baropodometric variables were evaluated using a baropodometric platform: the mean load pressure on the plantar surface, the total surface of feet, forefoot vs rearfoot loading, forefoot vs rearfoot surface, and the percentage of body weight on each limb. The tests were performed in three dental occlusion conditions: mandibular rest position (REST); voluntary teeth clenching (VTC); and cotton rolls placed between the upper and the lower dental arches without clenching (CR). The variables were analyzed through repeated measures ANOVA. The Mann-Whitney test was used to compare the postural parameters of the two groups. The level of significance was p < 0.05.

RESULTS

As to the intra-group analysis of TMD group, all posturographic parameters in both lower limbs showed a significant difference between REST vs CR (P < 0.001) and between VTC vs CR (p < 0.001), except for the percentage of body weight on each limb. The control group showed a significant difference between REST vs VTC, REST vs CR and VTC vs CR (p < 0.001) in the mean load pressure on the plantar arch, forefoot surface, rearfoot surface and total surface of feet. The mean load pressure on the plantar arch in VTC, and the forefoot and total surfaces of feet in CR (p < 0.05) were significantly higher in the TMD group in both limbs. The results of this study indicate that there are differences in the plantar arch between the TMD group and control group and that, in each group, the condition of voluntary tooth clenching determines a load reduction and an increase in surface on both feet, while the inverse situation occurs with cotton rolls. The results also suggest that a change in the load distribution between forefoot and backfoot when cotton rolls were placed between the dental arches can be considered as a possible indicator of a pathological condition of the stomatognathic system (SS) which could influence posture. Therefore the use of posture monitoring systems during the treatment of stomatognathic system is justified.

Dental malocclusion and body posture in young subjects: a multiple regression study

OBJECTIVES

Controversial results have been reported on potential correlations between the stomatognathic system and body posture. We investigated whether malocclusal traits correlate with body posture alterations in young subjects to determine possible clinical applications.

METHODS

A total of 122 subjects, including 86 males and 36 females (age range of 10.8-16.3 years), were enrolled. All subjects tested negative for temporomandibular disorders or other conditions affecting the stomatognathic systems, except malocclusion. A dental occlusion assessment included phase of dentition, molar class, overjet, overbite, anterior and posterior crossbite, scissorbite, mandibular crowding and dental midline deviation. In addition, body posture was recorded through static posturography using a vertical force platform. Recordings were performed under two conditions, namely, i) mandibular rest position (RP) and ii) dental intercuspidal position (ICP). Posturographic parameters included the projected sway area and velocity and the antero-posterior and right-left load differences. Multiple regression models were run for both recording conditions to evaluate associations between each malocclusal trait and posturographic parameters.

RESULTS

All of the posturographic parameters had large variability and were very similar between the two recording conditions. Moreover, a limited number of weakly significant correlations were observed, mainly for overbite and dentition phase, when using multivariate models.

CONCLUSION

Our current findings, particularly with regard to the use of posturography as a diagnostic aid for subjects affected by dental malocclusion, do not support existence of clinically relevant correlations between malocclusal traits and body posture.

Influence of voluntary teeth clenching on the stabilization of postural stance disturbed by electrical stimulation of unilateral lower limb

Studies on the relationship between dental occlusion and body balance have suggested that occlusion status contributes to the maintenance of postural balance. However, little has been reported about the effects of voluntary teeth clenching on the stabilization of postural stance in novel environments. In the present study we investigated whether teeth clenching influenced adaptation to the perturbation introduced by electrical stimulation of a unilateral lower limb. Subjects (12 adults) stood on a force plate, from which motion data were obtained in the horizontal plane with and without voluntary teeth clenching and were instructed to maintain the position throughout the experiment. We evoked a novel environment by supramaximal percutaneous electrical stimulation of the common peroneal nerve. Electromyograms (EMG) were recorded from the masseter and the peroneus longus (PL) muscles with bipolar surface cup electrodes. When the disturbed postural stance was generated by electrical stimulation, the maximum reaction force in the anterior-posterior (A/P) direction with teeth clenching (CL) was significantly smaller than that without voluntary teeth clenching (control; CO) (p<0.05) and the peak time of the ground reaction force/body mass (GRF/BM) in the A/P direction occurred earlier in the CL condition than CO (p<0.05). There were no significant differences in the peak-to-peak amplitude of GRF/BM and the peak time of GRF/BM, in the M/L direction under both CL and CO conditions. Thus, the present study showed that voluntary teeth clenching contributed to stabilization of the postural stance perturbed transiently by electrical stimulation. We concluded that voluntary teeth clenching plays an important role in rapid postural adaptation to the anterior-posterior perturbation in the upright position.