A Cross-Sectional Study of Developing Resting Masseter Activity in Different Angle Classifications in Adolescence

Abstract

The purpose of this study was to determine whether the development of masseter muscle activity at mandibular rest position is characteristic for different angle classifications. The sample consisted of 64 boys and 108 girls, aged ten to 18. Electromyographic (EMG) activity from the right and left masseter muscles was recorded using an EMG scanner. First or second order polynomials were used to separately model the age-related changes in resting muscle activity of each gender and Angle’s classification. The EMG activity of Class I boys and girls were expressed in positive second order polynomials. The EMG activities of Class II and Class III subjects were expressed in first order polynomials, and the EMG levels in Class III subjects were lower than in Class II subjects. These results indicated that development of resting activity levels might distinguish and characterize the anteroposterior mandibular position relative to craniofacial region.

Additional information

Notes on contributors

Kishio Sabashi

Dr. Kishio Sabashi received his D.D.S. degree from the Faculty of Dental Science, Gifu Dental College, Japan in 1979. He then practiced dentistry in private practice in Gifu until 1984. Dr. Sabashi received his Ph.D. at Osaka University Graduate School of Dentistry in 2002. His research interest is the close relationship between oral function and craniofacial morphology.

Issei Saitoh

Dr. Issei Saitoh received his D.D.S. degree from Faculty of Dental Science, Kyushu University, Japan in 1999 and a Ph.D. at the same university in 2003. He received the Award for Young Scientist from the Japanese Society of Stomatognathic Function in 2004. He fulfilled his intership at the Kyushu University Hospital for two years. He attended the Department of Pediatric Dentistry, Field of Development Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University as an assistant professor in 2005. Currently, he is an assistant professor at the Department of Pediatric Dentistry, Kagoshima University Medical and Dental Hospital. His research interest is development of oral function in children with primary dentition.

Haruaki Hayasaki

Dr. Haruaki Hayasaki received his D.D.S. degree in 1987 and a Ph.D. degree in 1992 from the Faculty of Dentistry in Kyushu University. He received a certification in pediatric dentistry from the Japanese Society of Pediatric Dentistry in 1992. He visited Baylor College of Dentistry, Department of Orthodontics (Dallas, Texas) as a visiting researcher from 1997 to 1999. He received the Award for Young Scientist from the Japanese Stomatognathic Function in 2000. Currently, he is an associate professor at Kagoshima University Graduate School of Medical and Dental Science.

Yoko Iwase

Dr. Yoko Iwase received her D.D.S. degree in 1997 from the Faculty of Dentistry, Kyushu University. She subquently worked for the Section of Pediatric Dentistry, Division of Oral Health, Growth, and Development, Kyushu University Graduate School of Dental Science from 1997 to 2001. In 2003, she received a Ph.D. from the same university and received a certification in pedodontics from the Japanese Society of Pediatric Dentistry. Currently, Dr. Iwase is a research associate in the Department of Dental Anesthesia, Kagoshima University Medical and Dental Hospital. Her research interest is occlusal contacts during masticatory movement in children with primary dentition.

Suguru Kondo

Dr. Suguru Kondo received his D.D.S. degree from the Faculty of Dental Science, Asahi University, Japan in 1997 and a Ph.D. at the same university in 2001. He worked at the Sabashi Clinic of Orthodontics and Pedodontics, Gifu, Japan from 2002 to 2004. Currently, he is working as a research associate in the Department of Oral and Maxillofacial Surgery, Fujita Health University School of Medicine. His research interest is development of oral function in children.

Emi Inada

Dr. Emi Inada received her D.D.S. degree from the Faculty of Dental Science, Kagoshima University, Japan in 2004. She fulfilled her internship at the Kagoshima University Hospital for two years. She subsequently has worked at the Section of Pediatric Dentistry, Division of Oral Health, Growth, and Development, Kagoshima University Graduate School of Dental Science since 2006. Her research interest is development of mandibular function in children with primary dentition.

Yoshihiko Takemoto

Dr. Yoshihiko Takemoto received his D.D.S. degree from the Faculty of Dental Science, Kagoshima University, Japan in 2005. He fulfilled his internship at the Kagoshima University Hospital for two years. Since 2007, he has worked at the Section of Pediatric Dentistry, Division of Oral Health, Growth, and Development, Kagoshima University Graduate School of Dental Science. His research interest is development of mandibular function in children with primary dentition.

Chiaki Yamada

Dr. Chiaki Yamada received her D.D.S. degree from the Faculty of Dental Science, Kagoshima University, Japan in 2006. She fulfilled her internship at the Kagoshima University Hospital for one year. Subsequently since 2007, she has worked at the Section of Pediatric Dentistry, Division of Oral Health, Growth, and Development, Kagoshima University Graduate School of Dental Science. Her research interest is development of mandibular function in children with primary dentition.

Youichi Yamasaki

Dr. Youichi Yamasaki received his D.D.S. degree in 1983 and a Ph.D. degree in 1989 from the Faculty of Dentistry in Kyushu University in Fukuoka, Japan. He worked as an assistant professor in the pediatric dental clinic at Kyushu University Dental Hospital. He has been a professor and chairman of Kagoshima University Graduate School of Medical and Dental Sciences since 2003. Dr. Yamasaki is studying the relationship between stomatognathic function and the effects of early treatment for malocclusion in children with primary, mixed dentition.