Analysis of muscle hardness in patients with masticatory myofascial pain.

Abstract

PURPOSE:

The aim of the present study was to access any changes in the muscle hardness of the masseter muscle between normal subjects and patients with myofascial pain during brief sustained isometric contractions at various bite force levels, and to compare muscle hardness, especially in terms of the recovery phase, after a clenching task.

MATERIALS AND METHODS:

Ten patients with masticatory myofascial pain and 10 age- and weight-matched normal healthy controls participated in this study. First, the hardness of the right masseter muscle was measured at the bite force of 0, 3, 6, and 9 kgf with a hand-held hardness meter. Then, the subjects were requested to exert a 9 kgf-clenching task for 30 seconds. The muscle hardness was again measured at 5, 30, and 120 seconds after the task, and the data obtained were compared with the muscle hardness before the clenching task.

RESULTS:

The results showed that there was no significant difference between the patients and the normal controls, while the muscle hardness increased with contraction in all subjects. The present findings also showed that the patients had a delayed return to baseline after the clenching task compared with the normal subjects, although an immediate increase after the clenching task was seen in all subjects.

CONCLUSION:

The results indicated that patients with masticatory myofascial pain have different muscle properties in the recovery phase after contraction, probably because of a slower intramuscular reperfusion.

• Authors: Koji Kashima, Kaori Igawa, Sho Maeda, Sumio Sakoda
• Journal: Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons (J Oral Maxillofac Surg) Vol. 64 Issue 2 Pg. 175-9 (Feb 2006) ISSN: 0278-2391 [Print] United States
• PMID: 16413887 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Adult
• Analysis of Variance
• Bite Force
• Case-Control Studies
• Female
• Hardness Tests (methods)
• Humans
• Male
• Masseter Muscle (physiopathology)
• Muscle Contraction (physiology)
• Muscle Tonus
• Temporomandibular Joint Dysfunction Syndrome (physiopathology)