Effect Of Head Posture Research Articles

The effect of head posture on facial soft tissue changes captured by white-light facial scanning

Abstract Objective To investigate whether changes in head posture have significant effects on facial soft tissues during white-light scanning. Materials and methods Thirty-four adult patients participated in the study in which 22 soft tissue landmarks were marked on the face of each subject using an oil-based pen. The subjects wore digital inclinometers on top of their heads, and sat relaxed with their heads orientated in natural head position (NHP), while a facial scan was captured. The subjects underwent a second facial scan in an upward 5°(U5), upward 10°(U10), downward 5°(D5), or a downward 10°(D10) direction with respect to the NHP. The NHP image was superimposed on the images taken at the different head postures and a single co-ordinate system was obtained. The axial reference plane (x-axis), the sagittal reference plane (y-axis) and the coronal plane (z-axis) were set with N’ as the zero point (0, 0, 0). The changes in position of each landmark caused by the change of head posture were measured. Results When the subject’s head was in the U5 and D5 posture, changes in landmark identification were not statistically significantly different. When the subject’s head was in the U10 posture, soft tissue Stmi and Li moved downward significantly. Soft tissue pogonion moved forward significantly in the D10 posture. Conclusions Soft tissue changes within 5° of the natural head posture were clinically negligible. If efforts to reproduce natural head position are carried out, reliable facial scanning images can be obtained without the support of any special head positioning tools.

Effect of head posture on tooth contacts in dentate and complete denture wearers using computerized occlusal analysis system.

Purpose:The purpose of the study was to assess and compare the occlusal contacts in dentate and edentulous patients wearing complete denture with varying head posture.Materials and Methods:Ad hoc sampling of 30 subjects (15 dentate and 15 edentulous) based on inclusion and exclusion criteria was done. Subjects were divided into two groups: dentate and edentulous. Each group was further divided into two subgroups based on two head postures-upright 90° and ventroflexed 30°. For recording of every posture, a new sensor was used, and the subject was asked to clench on the sensor in maximum intercuspation position at the two head postures.Results:Data were summarized as mean ± standard error and compared by Student's t-test using SPSS software (windows version 17.0 IBM corporation, New York, USA). A statistically significant correlation between head posture and contact area was found in dentate and denture wearers, i.e., tooth contact area varies with head posture.Conclusion:It was concluded that the occlusal contacts vary at different head posture in dentate as well as in denture wearers. With ventroflexion, the number of tooth contact decreased as compared to upright-erect position in both groups. Clinical implication - since the number of tooth contacts varies with varying head postures, it is recommended that the balancing of the contacts should be done at varying head postures.

Effect of Head and Tongue Posture on the Pharyngeal Airway Dimensions and Morphology in Three-Dimensional Imaging: a Systematic Review.

ABSTRACTObjectivesNatural head position is recommended to be optimal at cone-beam computed tomography acquisition. For standardization purposes in control of treatment outcome, it is clinically relevant to discuss, if a change of posture from natural head position may have an effect on the pharyngeal airway dimensions and morphology, during computed tomography, cone-beam computed tomography or magnetic resonance imaging acquisition. This was the aim of the present literature review study for purposes of valid evidence, which was hypothesized, to be present.Material and MethodsThis systematic literature review has been registered in PROSPERO database with following number: CRD42015024567. A systematic literature search performed in PubMed, Embase and Cochrane was carried out in order to evaluate if the effect of human head or tongue posture has an effect on upper airway dimensions and morphology in CT, CBCT or MRI. Study quality assessment was performed. Predictor variable was head and tongue posture. Endpoints were numerical values of upper airway dimensions and morphology.ResultsOverall 1344 articles (Embase 1063, PubMed 269, and Cochrane 12) resulted in four included publications. Quality assessments revealed poor quality and low-level evidence by 46 - 67% of the maximum achievable score. Heterogeneous methodology made a meta-analysis impossible, consequently a narrative synthesis was performed.ConclusionsLimited, poor quality and low evidence level literature is available on the effect of head posture on upper airway dimensions and morphology in three-dimensional imaging. Valid evidence requires a standardized method of head and tongue posture during image acquisition in future studies.

Biomechanical influences on head posture and the respiratory movements of the chest.

The head represents 6% of total body weight, therefore it can significantly affect the biomechanics of human posture control, movements and activities. When set out of vertical body axis, head position interferes with the work of the other links in the kinematic chain. The aim of our study was to evaluate the effect of head posture on the breathing activities of the chest. The research was conducted on a group of 65 patients (51 years ± 9.8 years), including 48 women and 17 men. Head posture and chest movements were assessed using a photogrammetric method. The results confirmed the existence of a negative correlation between head position in the sagittal plane and movements of lower ribs. Forward head posture resulted in lower amplitude of costal arch motion: for the transverse plane Spearman's R = -0.296, for the frontal plane; -0.273, -0.289. Tilting the head in the frontal plane also influenced the change in the biomechanics of breathing and contributed to a reduction of respiratory movements of the lower ribs Spearman's R = -0.260. Changing the position of the head causes disturbances in the three-dimensional shape of the chest and its respiratory movements.

A study on new patterns of cervical degenerative disease at a University Hospital In Western Region of Saudi Arabia

Introduction: Degenerative cervical spine disorders are referred to one or more of the following process: decrease in signal intensity of disc, posterior disc protrusion, anterior compression of spinal cord and dura, disc space narrowing, foraminal stenosis or osteophytosis. They are asymptomatic in most of the cases. However, the symptoms may vary between different populations. The aim of this study is to find out the pattern of degenerative cervical spine disease at King Abdulaziz university hospital. Material and Method: This was a Retrospective study From January 2005 to December 2010, the medical files of the patients were reviewed for demographic data (age and gender), clinical presentation, duration of symptoms, physical examination and progression of disease, radiological examinations with evidence of degenerative cervical. The results were presented in mean ± standard deviation; the correlation between variables was calculated by using Spearman's formula for the nonparametric values. Results: A total of 120 cases were reviewed. 63 (52.5%) were females and 57 (47.5%) were males. The mean age was 55.2± 12.8 years. The most common degenerative cervical spine changes were found at C 5-6 levels. The younger patients tended to have higher cervical spine level involvement P=0.0. The mean duration of symptoms was 41months. The younger patients tended to present more with the weakness and numbness p = 0.002, p = 0.005, respectively. 35 (29.1%) of patients found to have lost reflexes and 17 (14.1%) had exaggerated reflexes. Conclusion: Younger age group presents with more numbness, weakness and higher level in the cervical spine involvement. May be the new life style with more use of handheld devices and bad flexion posture of the neck plays a role in this aspect Further biomechamical studies need to be conducted to explore the effect of head posture on the cervical spine. The mean duration of symptoms prior to presentation was 41 months seems to be long, an education campaign need to be conducted to the community about the degenerative cervical disease risk factors, prevention and early recognition.

Effect of head posture on the healthy human carotid bifurcation hemodynamics

Head and neck postures may cause morphology changes to the geometry of the carotid bifurcation (CB) that alter the low and oscillating wall shear stress (WSS) regions previously reported as important in the development of atherosclerosis. Here the right and left CB were imaged by MRI in two healthy subjects in the neutral head posture with the subject in the supine position and in two other head postures with the subject in the prone position: (1) rightward rotation up to 80°, and (2) leftward rotation up to 80°. Image-based computational models were constructed to investigate the effect of posture on arterial geometry and local hemodynamics. The area exposure to unfavorable hemodynamics, based on thresholds set for oscillatory shear index (OSI), WSS and relative residence time, was used to quantify the hemodynamic impact on the wall. Torsion of the head was found to: (1) cause notable changes in the bifurcation and internal carotid artery angles and, in most cases, on cross-sectional area ratios for common, internal and external carotid artery, (2) change the spatial distribution of wall regions exposed to unfavorable hemodynamics, and (3) cause a marked change in the hemodynamic burden on the wall when the OSI was considered. These findings suggest that head posture may be associated with the genesis and development of atherosclerotic disease as well as complications in stenotic and stented vessels.

Effect of head posture on pediatric oropharyngeal structures: implications for airway management in infants and children

Although head and neck posture has direct effects on the upper airway in infants and children, many of these effects remain unclear or not well established. As airway patency and airway access are critical in sedated and/or unconscious children, recent developments in this area should be made known to pediatric anesthesiologists, intensive care physicians and other emergency caregivers. All recent studies observed large interindividual variability in anatomical measurements, especially in trachea length. More evidence has been gained that lateral position improves upper airway patency in sedated children. Several studies brought indirect information on head posture for laryngoscopy and intubation. The site of obstruction of the airway in sedated children in different postures is now more clear. Implications of head flexion and extension in intubated children have been extensively studied, and clinical consequences have been detailed. Due to large interindividual anatomic variability, depth marks set on the tubes by their manufacturers and guidelines regarding calculations of insertion depth should be made with caution in infants and neonates. Despite several studies, there is still little scientific evidence regarding proper head posture for laryngoscopy and intubation.

418 後面衝突時における頚部傷害に及ぼす頭部初期姿勢の影響

In this study, the effect of head posture on neck injury during rear-end impact was studied. First, a head-neck FE model was developed. Second, the behavior of the model during low-speed rear-impact, lateral bending and axial rotation was validated against experimental results. Third, rear impact simulations with 3 types of initial head postures including head-forward, lateral bending and axial rotation were conducted. Finally, the difference of the model behavior among 2 simulations was clarified, and that facet ligament strain during lateral bending and axial rotation simulation might exceed the strain during head-forward simulation was also clarified.

Effect of head posture on tracheal tube position in children.

Changes in the tracheal tube tip to carina distance were measured by radiographic screening following various head postures in 45 children undergoing cardiac catheterisation under general anaesthesia who were intubated via nasal and oral routes. Extension of the head moved the tracheal tube away from the carina and flexion moved it towards the carina in both routes. Endobronchial intubation was noted during neck flexion in a significant proportion of children intubated orally but none occurred during nasal intubation. Extension produced greater upward movement of the tracheal tube tip in the oral route than the nasal route. In contrast, flexion produced greater downward movement in the nasal route in some patients. The direction of movement with lateral rotation and use of a shoulder roll was inconsistent.

The postsurgical stability of oropharyngeal airway changes following maxillomandibular advancement surgery

Statement of the Problem: The purpose of this study was to evaluate: 1) the oropharyngeal airway changes at four different levels in the oropharynx, associated with maxillomandibular advancement surgery, 2) cervical-head posture changes, and 3) the long-term stability of the oropharyngeal airway and cervical-head posture changes. Materials and Methods: The sample includes 56 adults (8 males and 48 females) between 15 and 51 years of age. They were treated with multiple maxillary osteotomies and bilateral sagittal split ramus osteotomies to advance the maxilla and mandible. They were followed for an average of 31.3 months postsurgery. Each subject’s lateral cephalograms were taken with clinical Frankfort horizontal plane parallel to the floor and were traced/digitized twice and averaged to estimate surgical changes (T2-T1) and postsurgical changes (T3-T2). Method of Data Analysis: Lateral cephalograms traced by a single author and digitized with Dentofacial Planner Software Inc, which aligns the tracings to be analyzed on the S-N coordinates. The data were exported to SPSS software statistical package. Results: During surgery, the maxilla underwent counterclockwise rotation and 2- to 4-mm advancement. The anterior aspect of the mandible was advanced a mean of 13.11 mm (range, 2.4 to 22.4 mm). Postsurgical hard tissue changes were small and not statistically significant. The upper airway decreased significantly 4.1 mm (UPW-UPWa) immediately after surgery, middle (MPWmin-RV and MPW-U) and lower (LPWmin-BT) oropharyngeal airway increased 2.9, 3.7, and 4.4 mm, respectively. Over the 31.3 months postsurgical period, upper oropharyngeal airway increased 3.9 mm while middle and lower airway remained stable. The cervical-head posture rotated clockwise after surgery (4.8 degrees) and counterclockwise postsurgery (1.6 degrees). Conclusion: We conclude that maxillomandibular advancement surgery produced immediate increases in middle and lower oropharyngeal airway remaining stable over the longest follow-up period; surgery also produced significant increases in upper airway which were temporarily obscured by postsurgical edema. References Mehra P, Downie M, Pita MC, et al: Pharyngeal airway space changes after counterclockwise rotation of the maxillomandibular complex. Am J Orthod Dentofac Orthop 120:154, 2001 Wolford LM, Chemello PD, Hilliard F: Occlusal plane alteration in orthognathic surgery. Part I: Effect on function and esthetics. Am J Orthod Dentofac Orthop 106:304, 1994 Muto T, Takeda S, Kanazawa M, et al: The effect of head posture on the pharyngeal airway space (PAS). Int J Oral Maxillofac Surg 31:579, 2002 Funding Source: FAPESP.

The effect of head posture on the pharyngeal airway space (PAS)

The purpose of this study was to investigate the relationship between cranio-cervical inclination and pharyngeal airway space (PAS) by measuring these parameters at different head postures in the same subjects and to obtain a regression equation to correct the values measured. Fifty lateral cephalometric radiographs taken at five different head postures per individual were obtained from ten adults (seven males and three females) aged from 25 to 30 years with nose breathers and Class I occlusion. The changes in cranio-cervical inclination produced by head extension were correlated with changes in the variables describing the PAS. The OPT/NSL (cranio-cervical inclination in the second vertebrae) and C3-Me (distance between the third vertebrae and the Menton) correlated strongly with PAS-TP (the most proximal distance measured between the posterior pharyngeal wall and the tongue base) in the pharyngeal airway space (r=0.807 and 0.854 respectively). The regression equations were Y=−27.177+0.39 X (Y=PAS-TP, X=OPT/NSL), andY =−21.105+0.402 X (Y=PAS-TP, X=C3-Me), respectively. From these equations we could conclude that an increase of 10° in OPT/NSL or 10mm in C3-Me increased the pharyngeal airway space (PAS-TP) by about 4mm.

The Effect of Craniovertebral Fusion on Occlusion

The purpose of this study was to compare the effect of head posture on occlusion in subjects with craniovertebral fusion to that in normal unfused subjects. The experimental group consisted of five subjects (age range 30-76) who have all undergone previous surgical fusion of the craniovertebral region. The control group consisted of five unfused subjects matched by age, race and gender. Each subject's tooth contacts were recorded with a computerized dental instrument known as the T-scan. The tooth contacts were measured several times for each subject with the head tilted backwards (45 degrees) and forwards (30 degrees). A modification of Wilcoxon's rank sum test was used to compare the location of the tooth contacts and compare any variations between the craniovertebral-fused subjects' occlusal contact patterns and those of the normal nonfused patients. The results indicated that four of the five fused subjects had occlusal contact patterns that differed from their matched counterparts, thus suggesting that fusion of the craniovertebral region interferes with a normal mechanism that permits changes in head posture to shift tooth contact points. These results suggest that those who manage problems related to occlusion (craniofacial pain syndromes) need to consider the influence of the craniovertebral region on both occlusion and jaw position.

The Effect of Head Posture on Muscle Contact Position Using the T-Scan System of Occlusal Analysis

The purpose of this study is to investigate the effect of sagittal plane head-neck posture on initial tooth contacts (muscle contact position) using the T-Scan system of occlusal analysis. Thirty-five subjects from 14 to 72 years old were selected. Computerized T-Scan occlusal printouts were obtained on each subject with the head-neck in 45 degrees dorsiflexion and 30 degrees ventroflexion. To quantify the location of the contacts on the upper arch, the dotted lines appearing on the printout were assigned numerical values. Low numbers represent distal contacts and the higher the number, the more mesial the contact. Wilcoxon's Rank Sum Test was used to analyze the data. Results indicated that below the age of 30 years no significant relationship was demonstrated between head posture and muscle contact position. However, over the age of 30 there was an increasingly significant relationship between sagittal plane head-neck posture and initial occlusal contacts. Based on these findings, the authors recommend that management of occlusally related problems, i.e., temporomandibular disorders include an assessment of the craniovertebral region especially in patients over the age of 30 years.

The effect of head posture on muscle contact position: the sliding cranium theory.

The effect of head posture on initial occlusive contacts has been studied extensively by researchers in the basic sciences, dentistry, and physical medicine. The purpose of this paper is to review their theories and propose a new mechanism that attributes the effect of head posture to a change in the upper to lower jaw relationship. This mechanism is referred to as the sliding cranium theory. To understand how head posture alters initial tooth contact or muscle contact position, the arthrokinematics of the occipital-atlantal joint are covered in detail. The implication of the proposed new theory have relevance for dentists concerned with occlusal function and the treatment of temporomandibular joint dysfunction with temporomandibular repositioning, as well as for physical therapists who effect a change in head posture through mobilization procedures and therapeutic exercise. To conceptualize the proposed theory two easily performed tests are described. The sliding cranium theory presents a mechanical model that explains the interrelationship between the head-neck complex and the craniomandibular system in a way that has not been previously done.

The effect of head posture on the manometrics of the cerebrospinal fluid in cervical lesions: a new diagnostic test.

The effect of head posture on the manometrics of the cerebrospinal fluid in cervical lesions: a new diagnostic test.