Does Head Posture Have a Significant Effect on the Hyoid Bone Position and Sternocleidomastoid Electromyographic Activity in Young Adults?

Abstract

The aim of this study was to evaluate the associations between head posture (head extension, normal head posture, and head flexion) and anteroposterior head position, hyoid bone position, and the sternocleidomastoid integrated electromyographic (IEMG) activity in a sample of young adults. The study included 50 individuals with natural dentition and bilateral molar support. A lateral craniocervical radiograph was taken for each subject and a cephalometric analysis was performed. Head posture was measured by means of the craniovertebral angle formed by the MacGregor plane and the odontoid plane. According to the value of this angle, the sample was divided into the following three groups: head extension (less than 95°); normal head posture (between 95° and 106°); and head flexion (more than 106°). The following cephalometric measurements were taken to compare the three groups: anteroposterior head position (true vertical plane/pterygoid distance), anteroposterior hyoid bone position (true vertical plane-Ha distance), vertical hyoid bone position (H-H’ distance in the hyoid triangle), and C0-C2 distance. In the three groups, IEMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing bipolar surface electrodes on the right and left sternocleidomastoid muscles. In addition, the condition with/without craniomandibular dysfunction (CMD) in each group was also assessed. Head posture showed no significant association with anteroposterior head position, anteroposterior hyoid bone position, vertical hyoid bone position, or sternocleidomastoid IEMG activity. There was no association to head posture with/without the condition of CMD. Clinical relevance of the results is discussed.

Additional information

Notes on contributors

Saúl Valenzuela

Dr. Saúl Valenzuela received his D.D.S. degree in 1990 from the University of Chile. He is an academic of the Faculty of Odontology, University of Chile. Dr. Valenzuela is currently a staff member of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile. He devotes his professional time to work in oral rehabilitation in several private health institutions and in private practice.

Rodolfo Miralles

Dr. Rodolfo Miralles received his D.D.S. degree in 1975 from the University of Chile. He is a full professor and chief of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile. Dr. Miralles is a member of the International Association for Dental Research. He is also an associate editor of the “Chilean Odontology Journal”.

María José Ravera

Dr. María José Ravera received her D.D.S. degree in 1990 and obtained a postgraduate degree in orthodontics in 1996 from the University of Chile. She is currently a staff member of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile. Dr. Ravera is dedicated to orthodontic treatment in several private health institutions and in private practice.

Claudia Zúñiga

Dr. Claudia Zúñiga received her D.D.S. degree in 1990 and obtained a postgraduate degree in orthodontics in 1998 from the from the University of Chile. She is currently a staff member of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile. Dr. Zúñiga is dedicated to orthodontic treatment in several private health institutions and in private practice.

Hugo Santander

Dr. Hugo Santander received his D.D.S. degree in 1981 from the University of Chile. He is currently a staff member of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile. Since 1982, Dr. Santander has dedicated his professional time and energy to the diagnosis and treatment of cranio-cervical-mandibular (CCD) disorders in several private health institutions.

Marcelo Ferrer

Dr. Marcelo Ferrer received his D.D.S. degree in 2000 from the University of Chile. During his work on the study presented here, he was a research fellow of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile.

Jorge Nakouzi

Dr. Jorge Nakouzi received his D.D.S. degree in 2000 from the University of Chile. During his work on the study presented here, he was a research fellow of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile.