The relationship between occlusal support and physical exercise ability

Association of physical function with masticatory ability and masticatory habits: a cohort study

BACKGROUND

Few studies have evaluated masticatory ability and habits in relation to physical function. This study aimed to investigate the association of physical function with both masticatory ability and masticatory habits.

METHODS

In this cohort study, we followed up with 146 community-dwelling older adults aged 65-84 years for 1 year. Physical function domain scores on the Kihon Checklist were used to assess physical function. Masticatory ability was examined using objective measurements and self-administered questionnaires. Data on masticatory habits were obtained using self-administered questionnaires. The Mann-Whitney U test was used to analyze the association between masticatory ability and masticatory habits as exposures; logistic regression analysis was used to analyze the effect of exposure on the outcome.

RESULTS

A relationship was found between objective and subjective masticatory ability; however, no relationship was found between objective masticatory ability and masticatory habits. Furthermore, subjective masticatory ability and masticatory habits appeared to influence physical function 1 year later (odds ratio [OR]: 6.00, 95% confidence interval [CI]: 1.44-25.05; OR: 6.49, 95% CI: 2.45-17.22).

CONCLUSION

Masticatory ability and habits may be associated with a decline in physical function after 1 year in community-dwelling older adults. To maintain the physical function of these individuals, early intervention that addresses not only masticatory ability but also masticatory habits is necessary.

Effect of teeth clenching on handgrip force in adult men: role of periodontal mechanoreceptors

PURPOSE

Voluntary teeth clenching is shown to increase the strength of muscle reflexes contributing to the improvement of postural stability. However, the interaction between the handgrip strength and teeth clenching is not yet understood. In this study, we aimed to evaluate the change in handgrip force in response to voluntary teeth clenching, and its relation to the peripheral receptors that play a central role in the control of mastication.

METHODS

Thirty-six healthy men were divided into two groups: aged 50-59 years, no dental prosthesis, and 53-62 years with total dental prosthesis. Each individual was given handgrip and teeth clenching instructions for five experiments: only handgrip, teeth clenching followed by handgrip without teeth clenching, teeth clenching followed by handgrip with teeth clenching, and the repetition of the last two instructions while wearing mouth guards.

RESULTS

Our findings showed that maximum handgrip force decreased and the resistance to fatigue increased in complete edentulous individuals using appropriate prostheses. Also, the significantly lower maximum handgrip force and higher resistance to fatigue values of the participants with dental prosthesis using a mouth guard while teeth clenching, revealed the central roles of periodontal mechanoreceptors.

CONCLUSION

Decreases in masticatory sensory information processes influence handgrip force values which is the most important indicator of motor function. The lack of periodontal mechanoreceptors associated with dental prosthesis usage may lead to a loss in muscle strength.

Association Between Malocclusion and Academic Performance Among Mongolian Adolescents

Objective: Malocclusion has been reported to affect the daily lives of schoolchildren adversely, but little is known regarding the association between malocclusion and academic performance. We aimed to investigate the association between malocclusion and academic performance among adolescents in Mongolia.

Methods: We conducted a cross-sectional study of 767 students aged 7–16 years from two public schools in Ulaanbaatar, Mongolia. Three orthodontists evaluated the need for malocclusion treatment in the participants and determined the type of malocclusion using the Index of Orthodontic Treatment Need and dental casts. The academic scores of study participants in 20 subjects were provided by their schools. Z-scores within subjects were calculated and aggregated into both overall and in six groups of subject categories comprised of mathematics, science, social science, language, arts, and physical education. A multiple linear regression analysis was performed to determine the association between malocclusion, malocclusion type, and academic score adjusted for gender, age, school, and family income.

Results: Of the 767 students, 32.6% had malocclusion, and dental crowding was the most prevalent type (162 cases, 21.1%). Malocclusion was not significantly associated with the z-score of overall academic score [coefficient: 0.04, 95% confidence interval (CI): −0.11 to 0.19]; however, dental crowding was significantly associated with the overall academic score (coefficient: −0.19, 95% CI: −0.35 to −0.03), after adjusting for covariates. Other types of malocclusion were not associated with academic scores. Among the six subject categories, arts (coefficient: −0.20, 95% CI: −0.36 to −0.04) and physical education (coefficient: −0.24, 95% CI: −0.42 to −0.07) were significantly associated with dental crowding.

Conclusions: Schoolchildren in Mongolia with dental crowding may be prone to poor academic performance, particularly in arts and physical education classes. Further randomized controlled trials are needed to determine whether the treatment of crowding boosts academic performance.

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.

Duration and sequence of muscular activation in dentate individuals and complete denture wearers during simulation of activities of daily living

Occlusal support may influence muscular function during complex motor tasks. This study evaluated the duration and sequence of muscular activation of masticatory (temporal, masseter), postural head/neck (sternocleidomastoid, trapezius), postural trunk (rectus abdominis, paravertebrals), and low extremity strength (rectus femoris, gastrocnemius) muscles during simulation of activities of daily living (ADL) in edentulous women wearing complete dentures (n = 10) and in dentate women (n = 10). Electromyographic activity was recorded during tests of stand-up/sit down in the Chair, sit up/lie down in the Bed and lift/lower Bags. Occlusal support (dentures) had a significant effect on duration of muscular activation in the Chair Test: the masseter muscle activated longer with dentures during the standing movement. The masseter and sternocleidomastoid muscles showed significant alteration in their order of activation in non-denture-wearing women. For the Bed Test, dentures had significant effect for the gastrocnemius during the sitting-up phase and for the rectus abdominis during the lying-down movement. For the Bag Test, head/neck muscles were activated in a different order as a function of occlusal support. Anticipation of activation of the paravertebral muscles, rectus abdominis, and gastrocnemius was observed in dentate women compared with denture wearers. These findings suggest that occlusal support influences electromyographic activity of some muscles during simulation of ADL.

Sex differences in jaw muscle duty factors during exercise in two environments: A pilot study

It is unknown if females and males use jaw muscles similarly during exercise. This pilot study assessed jaw elevator muscle duty factors (DFs=time of muscle activity/total recording time) at repeated sessions to test if DFs are reliable and different between sexes during exercises in two environments. Ten female and seven male subjects recruited from university soccer teams provided informed consent. Surface electromyography was recorded from masseter and temporalis muscles during biting and leg-extension laboratory exercises. Average activities to produce 20N bite-forces for each muscle and subject determined thresholds (5-80%·T20N) for subject-specific DF calculations during exercises performed in laboratory and natural environments. Subjects self-recorded via portable electromyography equipment during in-field leg-extension and weight-lifting exercises. Effects of variables on DFs were assessed via ANOVA (α=0.05) and simple effects testing (Bonferroni-adjusted p⩽0.012). All subjects used jaw muscles during exercises in both environments. DFs between laboratory sessions were reliable (R=0.84). During laboratory exercises, male temporalis DFs were significantly higher than female DFs from both muscles (p⩽0.001). During in-field exercises females had higher DFs during weight-lifting while males had higher DFs during leg-extensions. In-field sex differences were significant at most thresholds and showed larger effect sizes for leg-extension compared to weight-lifting exercises.

The effect of intrapartum dental support use among nulliparous during the second stage of labor - a randomized controlled study

OBJECTIVE

We aimed to determine the effect of a dental support device (DSD) use on the course of labor and delivery in nulliparous women.

METHODS

A randomized, controlled, open-label study of nulliparous (at 37 + 0/7 and 41 + 3/7 weeks of gestation) in a single tertiary university-affiliated medical center. Exclusion criteria included maternal chronic diseases, multi-fetal gestation and fetal chromosomal or structural anomalies. Outcomes were analyzed according to the actual use of the DSD, and satisfaction questionnaires following delivery.

RESULTS

Overall, 191 women were randomized (93in the study group and 98 in the control group). The median duration of the second stage was similar between the groups (100.0 ± 91.0 versus 98.0 ± 128.8 min, p = 0.97) and the maximal VAS score was significantly higher in the DSD group (4.0 ± 8.5 versus 3.0 ± 6.8, p = 0.04). The rate of obstetrical interventions such as operative vaginal delivery or cesarean section during the second stage was significantly higher in the control group than in the study group (28.2% versus 12.3% and 6.4% versus 1.2%, respectively, p = 0.004), mainly due to prolonged second stage of labor (24.5% versus 8.6%, p = 0.005). Of the DSD group, 50.6% rated the use of the DSD as comfortable, 32.2% rated its effect on pain relief as high, 55.6% would recommend its use to their peers and 51.9% would like to use it in their consecutive delivery.

CONCLUSION

The use of a DSD among nulliparous women appears to decrease the need for obstetrical intervention due to prolonged second stage of labor, with fair satisfaction of patients.

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.

Duration of the second stage of labor while wearing a dental support device: a pilot study

AIM

Developing a method of maximizing maternal expulsive effort should be of great value in reducing the number of cesarean sections or instrumental deliveries. Various investigations have shown that use of a dental support device (DSD) increases the isometric strength of different muscle groups. The aim of our study was to investigate the role of a DSD in second stage of pushing.

METHODS

Nulliparous women with an uncomplicated singleton pregnancy course were randomly assigned either to a DSD group or to a non-device group. Duration of the second stage of labor was evaluated. Rates of cesarean section or instrumental delivery indicated for failure to descend in the second stage of labor were also evaluated. Satisfaction scores for the DSD group were evaluated (range 1-5).

RESULTS

Sixty-four subjects were enrolled in the study. Cesarean section and instrumental delivery were performed for 12 (18.8%) and 5 (7.8%) patients, respectively. There was no difference in obstetrical and neonatal demographics between the two groups. Among 64 enrolled patients, 38 (59.3%) were evaluated for the second stage of labor (n = 19 for each group). Duration of the second stage of labor in the DSD group was significantly shorter than in the non-device group: (median 19 min (interquartile interval, IQI, 9) vs 31 min (IQI, 23)), P < 0.001. One patient in the non-device group required a vacuum extraction for failure to descend. The mode of satisfaction score for the DSD group was 5 (59.3%).

CONCLUSION

Wearing a dental support device may shorten the second stage of labor, and may decrease the number of failures to descend requiring operative intervention.

CLINICAL TRIAL REGISTRATION

NCT00629369.

The relationship between the stomatognathic system and body posture

In recent years, many researchers have investigated the various factors that can influence body posture: mood states, anxiety, head and neck positions, oral functions (respiration, swallowing), oculomotor and visual systems, and the inner ear. Recent studies indicate a role for trigeminal afferents on body posture, but this has not yet been demonstrated conclusively. The present study aims to review the papers that have shown a relationship between the stomatognathic system and body posture. These studies suggest that tension in the stomatognathic system can contribute to impaired neural control of posture. Numerous anatomical connections between the stomatognathic system's proprioceptive inputs and nervous structures are implicated in posture (cerebellum, vestibular and oculomotor nuclei, superior colliculus). If the proprioceptive information of the stomatognathic system is inaccurate, then head control and body position may be affected. In addition, the present review discusses the role the myofascial system plays in posture. If confirmed by further research, these considerations can improve our understanding and treatment of muscular-skeletal disorders that are associated with temporomandibular joint disorders, occlusal changes, and tooth loss.

Effect of occlusion status on the time required for initiation of recovery in response to external disturbances in the standing position

BACKGROUND

To examine whether occlusion status contributes to improvement of postural balance.

METHODS

Thirty healthy adolescents (15 males and 15 females; mean age, 20.3; standard deviation (SD) 1.6 years) with no equilibrium or stomatognathic function abnormalities were examined. Occlusion is a term meaning "jaw clenching." Occlusion status was evaluated by measuring masseter activity using the EMG system. Balancing ability was evaluated using the EquiTest system, which measures sway of the center of gravity produced by rapid movement of force plates as an external disturbance (three intensity levels). The time required for initiation of recovery after application of the disturbance was calculated by measuring displacement of the center of foot pressure. Data were compared according to occlusion status.

FINDINGS

Little difference in latency was observed following a small disturbances; however, the greater the disturbance the shorter the latency with occlusion, while without occlusion, latency increased with increasing disturbance. A statistically significant interaction (P<0.001) between occlusion and external disturbance was also found.

INTERPRETATION

This study suggested that occlusion contributes to maintenance of postural balance and improvement of stability when unexpected sway occurs in the standing position.

Quality of life and masticatory function in denture wearers

Successful prosthodontic treatments for a patient with removable partial dentures including maxillofacial prostheses hopefully brings about psychological wellbeing as well as improved health. The purpose of this study was to investigate the relationship between quality of life (QOL) and the various aspects of denture function. At first, a questionnaire with a visual analog scale with 16 question items concerning denture and/or eating problems, the present state of health, psychological and physical wellbeing, life satisfaction, and QOL was developed. To discuss the validity and reliability of the questionnaire, 48 outpatients who wore a denture were asked to fill it out. Next, to discuss the difference in QOL of the patient with various kinds of dentures and conditions, 103 outpatients were asked to complete the newly developed questionnaire. The questionnaire which contained four factor areas with eight questions for denture patients was developed by factor analysis with Varimax rotation. The reliability of the QOL scale was confirmed by reliability analysis (Cronbach's alpha = 0.784). The QOL score of edentulous patients with a complete denture having some trouble chewing was significantly lower than that of other denture patients. It was suggested that the wearing of a denture significantly affected the QOL of elderly persons.

Effect of Dentures Wearing on Motor Reaction Time and Balance Function in Elderly People

OBJECTIVE

To investigate the influence of dentures wearing on the parameters of physical fitness, particularly on agility and balance function in elderly people.

DESIGN

A case control study.

SETTING

Motohachiohjimachi, Hachiohji, Tokyo, Japan.

METHODS

Motor reaction time was measured in the presence and absence of dentures in the subjects who were 1) in a sitting position and lifted the lower limbs as fast as possible in response to a stimulus (Sitting Group) and those who were 2) in a standing position and jumped upright as fast as possible in response to a light stimulus (Jumping Group). The effects of dentures wearing on balance function were investigated by comparing the measured values of static and dynamic body sway.

RESULTS AND CONCLUSIONS

Light-reaction time was not significantly influenced by dentures wearing in Sitting Group performing a light body movement that required little muscular force. In a relatively heavy body movement that required agility (i.e., jumping from the standing position), the reactivity changed depending on the muscular force; which might result in the difference of the reactivity due to dentures wearing (i.e., t-test showed a significant difference in the light-reaction time under clenching posture between with and without wearing dentures (p < 0.01)). No significant difference was observed in body sway under clenching posture between with and without wearing dentures.Therefore, we assumed that reaction speed varied depending upon dentures wearing.

Relationship between dental occlusion and physical fitness in an elderly population

BACKGROUND

The relationship between physical fitness and dental health status in elderly adults is still unknown. The purpose of the present study is to examine the relationship between physical fitness and occlusal condition of natural teeth in the elderly population. The sample consisted of 591 individuals aged 70 years and 158 aged 80 years selected from the registry of residents in Niigata city.

METHODS

Hand grip strength (kg), leg extensor strength (kg), leg extensor power (watts), stepping rate (time per 10 seconds), and one-leg standing time with eyes open (seconds) were measured. The Eichner index was used as a measurement of occlusal condition. It was based on existing natural tooth contacts between maxilla and mandible in the bilateral premolar and molar regions and determined the three groups of classification used. In comparing physical fitness with Eichner index, multiple regression models were developed to adjust for variables such as age, gender, height, body weight, past medical history, blood pressure, serum albumin concentration, presence of lower back pain, smoking habit, marital status, and education.

RESULTS

Multiple regression analyses revealed that leg extensor power (R(2) =.627, p <.05), stepping rate (R(2) =.159, p <.05), and one-leg standing time with eyes open (R(2) =.179, p <.05) showed significant correlations with the Eichner index.

CONCLUSIONS

Leg extensor power, stepping rate, and one-leg standing time with eyes open are useful indicators in evaluating lower extremity dynamic strength, agility, and balance function, respectively. These findings suggest that dental occlusal condition is associated with lower extremity dynamic strength, agility, and balance function in elderly adults.