Head and neck posture influences masticatory muscle electromyographic amplitude in healthy subjects and patients with temporomandibular disorder: a preliminary study

Abstract

Background: Despite the association of masticatory function with head posture and mandible movement, the impact of head posture on masseter muscle electrical activity remains unclear. This study aimed to investigate the electrical activity of the anterior temporal, masseter, superior trapezius, and sternocleidomastoid muscles in temporomandibular disorder (TMD) patients in three different head positions and compare the findings with those for healthy subjects.Methods: The study included 16 TMD patients and 17 healthy subjects. Surface electromyography (sEMG) was used to assess the bilateral anterior temporalis, masseter, superior trapezius, and sternocleidomastoid muscle activities. The maximal voluntary contraction (MVC) and root mean square (RMS) sequence of each muscle were measured in three head positions. Mixed analysis of variance was used to evaluate the effects of head posture on muscle electrical activity in each group. Results:The group differences for the bilateral masseter muscles were significant in the relaxation position, neutral head position (NHP), and relaxation position with tooth contact (P<0.05). In both groups, the basal RMSs of the bilateral anterior temporalis muscle in the relaxation position with tooth contact was significantly higher than that in the NHP (P<0.05). In both groups, the basal RMSs of the bilateral masseter muscles in the relaxation position with tooth contact was higher than that in the relaxation position and NHP, with significant differences (P<0.05).Conclusions: During the management of TMD patients, physical therapists should focus on patient education regarding maintenance of a relaxed position and establish appropriate rehabilitation programs to reduce muscle activity.

Changes in the craniofacial morphology and hyoid bone position in the neutral and forward head posture in healthy people

“…Moreover, a signi cant correlation was observed between the craniocervical position, hyoid bone position, and vertical craniofacial morphology. These results are consistent with those of previous studies [3,7,17,19].…”

Does head and cervical posture correlate to malocclusion? A systematic review and meta-analysis

“…When abnormal posture of head and neck takes place during active growth stage of patient, the normal development of craniofacial structure may be disrupted due to biomechanical and anatomical connection between neck muscles and craniofacial structure [1][2][3][4]. Moreover, according to the previous epidemiologic studies, patients suffering from neck disorders showed a higher percentage of craniomandibular disorders, which are often accompanied by malocclusion [5][6][7][8]. Therefore, a hypothesis that head and cervical posture correlates to malocclusion was put forward and widely reported in the field of orthodontics and orthopedics [9].…”

Surface Electromyography in Dentistry—Past, Present and Future

“…In addition to what has already been described in the introduction, i.e., the use of sEMG for assessing muscle activity during physiological and parafunctional activities [ 6 ], it is also used in the diagnosis of temporomandibular joint and masticatory muscle function and treatment of the TMDs [ 7 , 8 , 9 , 10 ]. Studies on the influence of psychological [ 11 , 12 , 13 , 14 ] and physical state on changes in the bioelectrical activity of the masticatory muscles appear on the sEMG [ 15 , 16 , 17 , 18 ].…”

“…In the field of dentistry, sEMG has become a valuable tool for assessing muscle bioelectrical activity during physiological and parafunctional activities [ 6 ], it is also used in the diagnosis of temporomandibular joint and masticatory muscle function and treatment of temporomandibular disorders (TMDs) [ 7 , 8 , 9 , 10 ]. Studies on the influence of psychological [ 11 , 12 , 13 , 14 ] and physical state on changes in the bioelectrical activity of the masticatory muscles appear on sEMG [ 15 , 16 , 17 , 18 ]. The usefulness of sEMG has also been demonstrated in orthodontics, primarily in the monitoring of therapy.…”