The Effect of Tooth Clenching and Grinding on Anterior Temporalis Electromyographic Activity in Healthy Subjects

Abstract

The aim of this study was to determine the effect of tooth clenching and grinding on anterior temporalis electromyographic (EMG) activity. The sample included 30 healthy subjects with natural dentition and bilateral molar support, 15 with bilateral canine guidance and 15 with bilateral group function. An inclusion criterion was that subjects have to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the left and right anterior temporalis muscles. EMG activity was recorded during the following conditions: A. eccentric grinding from intercuspal position to the right lateral edge-to-edge contact position; B. clenching in right edge-to-edge lateral contact position; and C. concentric grinding from right lateral edge-to-edge contact position to intercuspal position. On the working side, EMG activity was not significantly different between conditions in both occlusal schemes. On the nonworking side, EMG activity was significantly higher during condition C than condition B in both occlusal schemes (mixed model with unstructured covariance matrix). When comparing by side, EMG activity was significantly higher during conditions A and B on the working side than on the nonworking side. However, there was no significant difference during condition C. EMG activity was significantly lower with canine guidance than group function on the working side (in all conditions) as well as during concentric grinding on the nonworking side. These results could explain muscular symptoms in the anterior temporalis muscles if the subject is experiencing parafunctional habits either while awake and/or sleep that exceed the individual’s adaptation capability.

Additional information

Notes on contributors

Mario Felipe Gutiérrez

Dr. Mario F. Gutiérrez received his D.D.S. degree in 2007 from the University of Chile. He is ad-honorem academic of the Restorative Department and of the Oral Physiology Course of the Faculty of Odontology, University of Chile. Dr. Gutiérrez 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.

Aler Fuentes

Dr. Aler Fuentes received his D.D.S. degree in 2006 from the University of Talca, Chile. He is an academic of the Faculty of Odontology, University of Chile. Dr. Fuentes is currently a staff member of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile. He is in training to obtain a Master of Dental Sciences at the University of Chile.

Gabriel Cavada

Mr. Gabriel Cavada received his statistical technician degree in 1996 from the University of Chile and a Master of Biostatistics in 1998 from the same university. He is an assistant professor of the Public Health School, Faculty of Medicine, University of Chile. Mr. Cavada is a member of the Chilean Chapter of Biometrics Society and the Chilean Statistics Society.

Saúl Valenzuela

Dr. Saúl Valenzuela received his D.D.S. degree in 1990 from the University of Chile. He is an academic of the Prosthetics Department, 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.

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 time and energies to diagnosis and treatment of cranio-cervicalmandibular (CCD) disorders in several private health institutions.

María Javiera Fresno

Dr. Maria Javiera Fresno, received her D.D.S. degree in 1988 from the University of Chile and a Master of Oral Rehabilitation in 2006 from the Andrés Bello University, Chile. She is a member of Oral Rehabilitation Department of Andrés Bello University, Chile. She is an academic of the Faculty of Odontology, University of Chile. She is currently a staff member of the Oral Physiology Laboratory, Biomedical Sciences Institute, Faculty of Medicine, University of Chile. She devotes her professional time to work in oral rehabilitation in private practice.