Relationship Between Occlusion and EMG Activity of the Masseter Muscles During Clenching at Maximal Intercuspal Position: A Comparative Study Between Prognathics and Controls

ABSTRACT

In the prognathic (P) patient group clenching at maximal intercuspal position (MIP), we found that the Ar-Go-Me angle is greater than in the control group (C = 120.9° ± 7° vs. P = 134.4° ± 5.2°); the same as the masseter fibers angle (α). The average EMG voltage class was similar in both groups (C = 1488.5 ± 303.4 μvolt vs. P = 1317.6 ± 293.4 μvolt). The mean total number of contact points in tooth arches was greater in the control group than in the patient group (C = 5.77 ± 0.43 vs. P = 3.07 ± 0.29), and there was a greater number of contact points between both premolar and molar areas. Both the control group and the patient group showed balanced occlusion in the premolar and molar areas. Therefore the finding of a similar mean EMG value between the control group and the patients emphasizes the importance of balanced contact points in the posterior areas.

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Notes on contributors

Hernán Cárdenas

Hernán Cárdenas is a pharmacist and received his M.Sc. degree in 1986 from the University of Concepción Chile. He is working as an Assistant Professor of Physiology at the Department of Physiology, Faculty of Biological Sciences of the same university. He is the Director of the Laboratory of Electrophysiology, performing research in the area of dentistry. Dr. Cárdenas has published several papers and is a member of the Association of Dental Research in Chile.

Armando Ogalde

Dr. Armando Ogalde has a D.D.S. degree and received his M.Sc. degree in 2000 from the University of Concepción Chile. He is on the laboratory staff of the Department of Physiology, Faculty of Biological Sciences of the same university. Dr. Ogalde is doing research in the area of dentistry in partnership with the Clinical Hospital of Concepción, Chile.