Integrated electromyography of the masseter on incremental opening and closing with audio biofeedback: A study on mandibular posture

Citation
Md. Gross et al., Integrated electromyography of the masseter on incremental opening and closing with audio biofeedback: A study on mandibular posture, INT J PROST, 12(5), 1999, pp. 419-425
Citations number
58
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Dentistry/Oral Surgery & Medicine
Journal title
INTERNATIONAL JOURNAL OF PROSTHODONTICS
ISSN journal
0893-2174 → ACNP
Volume
12
Issue
5
Year of publication
1999
Pages
419 - 425
Database
ISI
SICI code
0893-2174(199909/10)12:5<419:IEOTMO>2.0.ZU;2-R
Abstract
Purpose: The purpose of this study was to test the hypothesis of a minimum electromyographic (EMG) rest position based on masseter surface EMC recordi ngs of incremental opening and closing of the mandible with simultaneous au dio EMG biofeedback. Materials and Methods: Nineteen alert subjects in an u pright seated position opened and closed the mandible in 1-mm increments 20 mm interincisally. An electronic recording device allowed each subject to maintain the vertical dimension of each increment while simultaneously redu cing right masseteric muscle activity to the minimum possible level using a udio EMC biofeedback. integrated EMC masseteric activity was recorded at ea ch static opening and closing increment. Results: A mean plateau of integra ted EMC output for all subjects with no minimum EMG point or circumscribed minimum MC range for any of the nineteen subjects was shown. Analysis of va riance for repeated measures showed no difference in opening and closing EM C levels (P = 0.27) and no interaction between opening, closing, and change in vertical dimension (P < 0.0001). Conclusion: These results, with those of other studies, raise questions regarding the validity of the concept of a unique physiologic rest position of the mandible with the masseter or ass ociated muscles at minimum muscle activity. The idea of overlapping postura l ranges appears to be more appropriate.