Effects of experimental insoles on body posture, mandibular kinematics and masticatory muscles activity. A pilot study in healthy volunteers

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.

Effects of Occlusal Splints on Spinal Posture in Patients with Temporomandibular Disorders: A Systematic Review

There is still a gap in the scientific knowledge on the linkage between craniofacial structure and spinal postural control in temporomandibular disorder (TMD) patients. This systematic review aimed to assess the role of occlusal splints on spinal posture of TMD patients. PubMed, Web of Science, and Scopus were systematically searched from inception until 5 January 2022 to identify observational studies with a longitudinal study design presenting: patients with diagnosis of TMD according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD); occlusal splint therapy as intervention; postural assessment as outcome. Out of 133 records identified, 104 were suitable for data screening, and only 7 articles were included satisfying the eligibility criteria. We found that occlusal splints might have a positive effect on posture in TMD patients, albeit there is little evidence of appropriate investigation for postural assessment. This systematic review suggested that the occlusal splint might be considered a non-invasive therapeutic approach for patients with TMD. However, the low number of studies with high-quality methodology in these patients showed an urgent need for further research using combined force platform stabilometry and kinematic evaluation of the spine to investigate the impact of occlusal splints on posture.

Análise do equilíbrio postural estático e da intensidade das dores musculoesqueléticas após o uso de palmilhas proprioceptivas por militares do serviço ostensivo

RESUMO Para a manutenção do equilíbrio, o organismo utiliza os sistemas visuais, vestibulares e proprioceptivos, que enviam informações para o sistema nervoso central acerca das condições do corpo com o objetivo de estabilizá-lo. Este estudo avaliou o efeito das palmilhas proprioceptivas sobre o equilíbrio postural estático e as dores musculoesqueléticas após dois meses de uso, por meio de uma pesquisa analítica longitudinal com 15 militares saudáveis do sexo masculino com média de idade de 34±7,5 anos. Eles foram submetidos à avaliação do equilíbrio por meio da plataforma Medicapteurs® e pelo protocolo CNT. Não houve diferença estatística para os desvios do corpo e velocidade do centro de pressão. A pressão plantar teve mudança estatisticamente significante para o pé esquerdo e o pé direito correspondendo a p=0,0001 e p=0,0007, respectivamente. Houve redução das médias de dores nos joelhos, pés e calcanhares e diminuição significativa da dor lombar, com p=0,0180. O equilíbrio estático não foi alterado significativamente com o uso das palmilhas proprioceptivas pelos militares, contudo elas proporcionaram melhor redistribuição das pressões plantares e parecem atenuar as dores musculoesqueléticas das extremidades inferiores. Por isso as palmilhas podem ser consideradas para esse grupo uma terapêutica de prevenção contra lesões relacionadas à sua atividade laboral.

Comparison between the musician-specific seating position of high string bow players and their habitual seating position - a video raster stereographic study of the dorsal upper body posture

Background

Effects of playing high stringed bow instruments on the upper body posture have not been analysed so far. The instrument-specific seating position when playing in an orchestra is compared to the habitual seating position.

Methods

Three dimensional back scans were performed in 13 professional violinists and viola players of a radio orchestra (8 f / 5 m). Trunk position in their habitual seating position and in the instrument- specific seating position imitating playing was compared. Statistical differences were calculated using Wilcoxon Matched Pairs Test with Bonferroni Holm correction.

Results

Significant differences were found between the seated position with instrument and without (p < 0.001, 0.03, 0.02 or 0.01) in the spine (trunk length, sagittal trunk decline, lumbar bending angle, maximal rotation, standard deviation rotation, lumbar lordosis), the shoulder (scapula distance, scapula rotation, scapula angle right) and pelvis distance.

Conclusions

Playing an instrument changes the static seating position by increased rotation of the spine and specific shoulder adaptations holding the instrument (left arm) and the bow (right arm), with minor effects on the pelvis. This forced position may result in chronic health effects. The method used in this study is an approach to better understand the involved muscular structures and possible resulting health damages.

Fit to play: posture and seating position analysis with professional musicians - a study protocol

Background

Musical performance-associated musculoskeletal disorders (MSD) are a common health problem among professional musicians. Considering the manifold consequences arising for the musicians, they can be seen as a threat for their professional activity. String players are the most affected group of musicians in this matter. Faults in upper body posture while playing the instrument, causing un-ergonomic static strain on the back and unergonomic limp-movements, are a main reason for musculoskeletal disorders and pain syndromes.

Methods

A total of 66 professional musicians, divided into three groups, are measured.

The division is performed by average duration of performance, intensity of daily exercise and professional experience. Video raster stereography, a three-dimensional analysis of the body posture, is used to analyse the instrument-specific posture. Furthermore the pressure distribution during seating is analysed. Measurements are performed because the musician is sitting on varying music chairs differing in structure and/or construction of the seating surface. The measurements take place in habitual seating position as well as during playing the instrument.

Results

To analyse the influence of different chairs, ANOVA for repeated measurements or Friedman-test is used, depending on normality assumptions. Comparison of posture between amateur musicians, students, and professional orchestral musicians is carried out the non-parametric Jonckheere-Terpstra-test.

Conclusions

Our method attempts to give the musicians indications for the right music chair choice by analyzing the chair concepts, so that thereby preemptively MSD can be reduced or prevented.

Craniomandibular System and Postural Balance after 3-Day Dry Immersion

The objective of the study was to determine the influence of simulated microgravity by exposure to dry immersion on the craniomandibular system. Twelve healthy male volunteers participated in a 3-day dry immersion study. Before and immediately after exposure we measured maximal bite force using piezoresistive sensors. The mechanical properties of the jaw and cervical muscles were evaluated before, during, and after dry immersion using MyotonPRO. Because recent studies reported the effects of jaw motor activity on the postural stability of humans, stabilometric measurements of center of pressure were performed before and after dry immersion in two mandibular positions: rest position without jaw clenching, and intercuspidal position during voluntary teeth clenching. Results revealed no significant changes of maximal bite force after dry immersion. All postural parameters were significantly altered by dry immersion. There were however no significant differences in stabilometric data according to mandibular position. Moreover the masseter tonicity increased immediately after the end of dry immersion period. Dry immersion could be used as a valid model for studying the effects of microgravity on human subjects. However, 3 days appear insufficient in duration to evaluate the effects of weightlessness on maximal bite force. Our research suggests a link between postural disturbance after dry immersion and masseter tonicity.