Translation and Rotation of the Mandible During Habitual Mouth Opening Movement in Children with Anterior Reverse Bite in the Primary Dentition

ABSTRACT

Translation and rotation ot the mandible during habitual mouth opening movements were studied in 13 children with skeletal-based anterior reverse bite (reverse bite group) and in 13 children with normal occlusion (normal occlusion group) whose dental stage was the primary dentition. Movements were recorded by an opto-electronic movement-analyzing system that could measure mandibular movements with six degrees of freedom. Inferior translation of the mandible was analyzed at the left primary central incisor, both of the primary canines, and both of the primary second molars. Anterior translation of the mandible was analyzed at both of the condyles. Rotation of the mandible was measured in the sagittal plane. The results showed that the associations between the translation and rotation of the mandible during habitual mouth opening in the reverse bite group differed from those in the normal occlusion group. The reverse bite group had greater anterior translation of both of the condylar points than did the normal occlusion group. No significant differences were found in the inferior translation or rotation of the mandible between the two groups.

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Notes on contributors

Megumi Nagata

Dr. Megumi Nagata received her D.D.S. degree in 1992 from Faculty of Dentistry. Kyushu University. She fulfilled her internship at the Kyushu University Hospital for three years and worked at the same hospital for two years. Dr. Nagata subsequently joined the Section of Pediatric Dentistry, Division of Oral Health, Growth, and Development, Kyushu University Graduate School of Dental Science in 1997. Currently, she is a graduate student.

Youichi Yamasaki

Dr. Youichi Yamasaki received his D.D.S. degree from Faculty of Dentistry in Kyushu University in Fukuoka, Japan, in 1983, and a Ph.D. at the same university in 1989. He is an assistant professor in the pediatric dental clinic in Kyushu University Dental Hospital and received an instructor's specialist's license for pediatric dentistry from the Japanese Society of Pediatric Dentistry in 1999. Dr. Yamasaki has done early treatment in many cases of malocclusion in children with primary and early mixed dentition and has published articles and books on the subject.

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 certification as a Pedodontist from the Japanese Society of Pediatric Dentistry in 1992. He visited Baylor College of Dentistiy, Department of Orthodontics (Dallas, Texas) as a visiting researcher from 1997 to 1999. Dr. Hayasaki received the Award for Young Scientist from the Japanese Society of Stomatognathic Function in 2000. Currently, he is a research associate in the Section of Pediatric Dentistry, Division of Oral Health, Growth, & Development, Kyushu University, Faculty of Dental Science.

Minoru Nakata

Dr. Minoru Nakata is Professor of Pediatric Dentistry, Division of Oral Health, Growth, and Development, Kyushu University Faculty of Dental Science. He received his D.D.S. degree from Tokyo Medical and Dental University School of Dentistry in 1964 and a Ph.D. in 1968. Dr. Nakata was awarded the NIH Forgaty International Fellowship and attended Medical Genetics, Indiana University of Medicine from 1971–1973. His book, “Occlusal Guidance in Growing Children” has been published in four languages as well as Japanese.