Relationship Between the Number of Occlusal Contacts and Masticatory Muscle Activity in Healthy Young Adults

ABSTRACT

The electromyographic (EMG) potentials of left and right masseter and temporalis anterior muscles were recorded in 23 healthy young adults during: 1. a 3-second maximum voluntary clench (MVC) on cotton rolls positioned on the posterior teeth (standardized recording); and 2. a 3-second MVC in intercuspal position. EMG potentials recorded in intercuspal position were standardized as a percentage of the mean potentials of the standardized recording, and the EMG muscle activity was calculated. The number of occlusal contacts in intercuspal position was assessed by using eight μm thick shim stocks. Two groups of subjects with either 1. Less than ten occlusal contacts (11 subjects with “few contacts”); or 2. At least ten occlusal contacts (12 subjects with “many contacts”) were selected. The MVC muscle activity in the “few contacts” group was significantly lower than that recorded in the “many contacts” group (p<0.005). In conclusion, the number of occlusal contacts and masticatory muscular function are significantly related, at least in young adults with a sound stomatognathic apparatus.

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Notes on contributors

Virgilio F. Ferrario

Dr. Virgilio F. Ferrario received his Ph.D. degree in bioengineering from the Polictecnico of Milan, Italy in 1969. He received his M.D. degree from the University of Milan School of Medicine, in Italy in 1980. He is a Professor of Human Anatomy at the Dental School of Milan University, and Director of the Laboratory of Functional Anatomy of the Stomatognathic Apparatus, Department of Human Anatomy, Faculty of Medicine, University of Milan, Italy. Dr. Ferrario has been involved in research on the anatomical bases of stomatognathic function and malfunction and is currently developing functional tests to analyze the activity of masticatory muscles.

Graziano Serrao

Dr. Graziuno Serrao received his M.D. degree from the University of Milan School of Medicine, Italy in 1984, and his Ph.D. in Morphological Sciences from the same University in 1996. He is currently a staff member of the Laboratory of Functional Anatomy of the Stomatognathic Apparatus.

Claudia Dellavia

Dr. Claudia Dellavia received her D.D.S. degree from the University of Milan School of Dentistry, Italy in 1999. She has been working at the Laboratory of Functional Anatomy of the Stomatognathic Apparatus since 1994. Dr. Dellavia is currently attending at a postgraduate course in Morphological Sciences in the University of Milan.

Elisabetta Caruso

Ms. Elisabetta Caruso is a graduate student of the Dental School of Milan University. She is preparing her DDS thesis at the Laboratory of Functional Anatomy of the Stomatognathic Apparatus.

Chiarella Sforza

Dr. Chiarella Sforza received her M.D. degree from the University of Milan School of Medicine, Italy in 1986, and her Ph.D. degree in Sports Medicine in 1989 from the same University. She is a Professor of Human Anatomy at the School of Sport Sciences of Milan University. She has been a staff member of the Laboratory of Functional Anatomy of the Stomatognathic Apparatus since its foundation in 1989, where she coordinates research activities.