The stomatognathic system comprises a complex set of orofacial structures, linked by a broad network of sensomotor neural connections peripheral to the central nervous system, which are related to masticatory, phonation, and deglutition functions.
A temporomandibular system may be conceived of as part of the stomatognathic system, including temporomandibular joints (TMJ), masticatory muscles and associated ligaments, plus the aforementioned neural structures. Its functions are mandible positioning and moving, as well as maintaining its rest posture. Whether of morphologic or functional origin, failure of these musculoskeletal structures bring about diverse clinical conditions which have been generic ally defined as temp oromandibular dysfunctions (TMD).
Though traditionally both physiology and treatment of the stomatognathic system have been conceived of as apart from the system that manages global body posture, there is clinical evidence of mutual interdependence between both. Such interrelations are manifested by morphologic or functional alterations in the stomatognathic system structures, brought about by acute (1-16) or chronic (17,18) changes in body posture or vice-versa. (19-26)
The physiology involved in these interrelations has broadly been explained by biomechanical theories, (8,27,28) i.e., that changes of tissue tension-compression in one region are generated by changes in another--and by neuromuscular-grounded theories, (9,10,12,15) i.e., changes in the electromyographic activity of muscles in one region might be due to position changes in the other.
According to a major physical therapy current, muscle groups responsible for posture maintenance are organized and operate following a pattern known as muscle chains. (29-32) Posture changes in a muscle segment could lead to the elongating or shortening of adjacent muscles, which can interfere in the physiology of the masticatory muscles. Muscle chains are the fundamentals of a body posture rehabilitation technique called global posture reeducation (GPR). (29-34)
In view of the available evidence of functional interrelation between body posture and mandible operation, some authors suggest that changes in body posture may be closely linked to TMD. (35-37)
Several studies have reported a higher frequency of body posture alterations in subjects with TMD when compared to healthy subjects, (38-48) while others found no relationship between body posture and TMD. (49-51)
Similarly, a previous study (52) under the same authorship analyzed the body posture of subjects with TMJ internal derangement using a quantitative analysis of photograph tracings and comparing them to those of a group with healthy temporomandibular system. No significant differences in body posture could be found between the two groups. The same subject sample had their body posture analyzed by means of cervical spine radiography in another study, (48) where a higher frequency of hyperlordosis was found in individuals with TMJ-id than in healthy subjects.
The present study aims at assessing body posture by the analysis of muscle chains in the same sample of individuals with TMJ-id analysed in those previous studies, searching for possible relations between TMD severity and changes in body posture.
Materials and Methods
The subjects who took part in the study were 50 individuals aged 16 to 35, who were divided into test and control groups. The former was made up of 30 subjects with TMJ-id (three male, 27 female, mean age 21.7 [+ or -] 3.6 yrs). The control group had 20 subjects (six male, 14 female, mean age 22.9 [+ or -] 5.3 yrs). Groups were homogenous as to gender, age and ethnicity (Table 1).
The test group subjects were randomly selected among outpatients at the Orofacial Pain and TMJ Clinic at the Hospital das Clinicas of the University of Sao Paulo (USP) School of Medicine; all subjects presented symptoms compatible with TMJ-id, with or without an associated myogenous component.
The control group consisted exclusively of individuals with fully healthy temporomandibular system, assessed by the anamnestic and dysfunctional indexes proposed by Helkimo, (53) with no previous or current history of TMD.
A detailed account on selection criteria for these groups has been previously published. (47,48,52) All subjects gave their explicit consent to take part in the study, which was approved by the Bioethics Committee of the USP Hospital das Clinicas.
Procedures
The subject evaluation is comprised of two steps:
1. evaluation of the stomatognathic system, especially of the temporomandibular system (TMJ, masticatory muscles, and associated ligaments) and of dental occlusion; and 2. evaluation of the body posture through photographic analysis.
Evaluation of the stomatognathic system: The protocol used included detailed anamnesis of patients' complaints; a questionnaire made up by the Orofacial Pain and TMJ Team of the USP Hospital das Clinicas, (54) which standardized the history of complaints of craniofacial pain and TMD, as well as some aspects of general health that might influence the complaint; and the Helkimo anamnestic and dysfunctional indexes. (53)
Based upon the data obtained, a profile of each subject was established according to presence, quantity, and frequency of craniofacial pain, dental and occlusal condition, as well as the degree of functional health or illness of the temporomandibular system.
Photographic evaluation of body posture: A qualitative posture evaluation was made using an analysis of photographs. (44,55) Photographs for the global evaluation of posture (full body) were taken with subjects in orthostatic position (with the exception of the flexion one) in frontal, lateral, and dorsal views. For the evaluation of lateral head and neck posture, a close-up was taken of the lateral profile. (43) A sixth shot was taken of subjects in maximum trunk flexion aiming to touch the toes with their hands without bending the knees (Figure 1). The latter for visualization of the tibiotarsal angle, of which alterations point to shortening of the posterior muscle chain. (56)
Wearing sports clothing, with feet together and eyes aimed at the horizon, each subject was positioned on a ladder-type step, at a distance of 2.60 m from a photographic camera (Canon AV-1, 35-50 mm lenses, Canon Corp., Tokyo, Japan) placed on a tripod at the level of the subject's umbilical scar. Marks were made with self-adhesive circular labels (0.5 cm radius) in specific anatomical points: acromions, lower borders of the scapulae, antero-superior and postero-superior iliac spines, lateral ankles, spinal apophysis of C7, and greater trocanter. Evaluation of the lateral posture of head and neck followed a similar procedure, with the subject standing at 1.40 m from the camera tripod, with the camera placed at mandibular angle level.
The six photographs of each individual were printed in standard size (10x15 cm) and laid down so as to allow viewing the full sequence on the same page (Figure 1).
The subjects clinical examination and photograph processing followed the same patterns described in previous studies. (47,48,52)
Source Citation
Tidak ada komentar:
Posting Komentar
Please Comment..!!