Hemodynamics in the masseter muscle : a potential method to trace the pathogenesis of muscle pain.

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11672015
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Surgical dentistry
• Research Institution: Jikei University School of Medicine
• Principal Investigator: SUGISAKI Masashi Jikei University School of Medicine School of Medicine Associate Professor, 医学部, 助教授 (30085873)
• Project Period (FY): 1999 – 2000
• Keywords: masseter muscle / near infra-red spectroscopy / blood flow / sex differences / muscle pain / temporomandibular disorders

Research Abstract

Temporomandibular disorders (TMD) is a common pain condition with greater treatment demand among females. Muscle ischemia is one of the important factors for muscle fatigue and pain. Although lower values of hematocrit and hemoglobin (Hb) content values have been shown in women, there have no report about sex differences in Hb oxygenation state of the masseter muscle. Aims : To determine sex differences exist in the tissue oxygen saturation (StO_2) and Hb oxygenation state of the human left side masseter muscle in the rest position of healthy volunteers. To determine differences exist in StO_2 and Hb oxygenation between painful and control sides of the masseter muscles in the female patients with TMD.Methods : One near-infrared spectroscopy (NIRS) was used to measure these parameters in healthy adult volunteers (10 women, 10 men) as the first study. Two NIRSs were used to measure in female patients with TMD (10 patients) as the second study. In the first study, data were corrected in s ampling 1 Hz during 60 sec (60 data). In the second study, data were corrected in the same sampling protocol at the both side using each NIRS, then data were corrected through two NIRSs (120 data). Results : In the first study, StO_2 were 4554 in men and 4578 in women. The OXHb, deOXHb and THb in men were 21761, 6981 and 28743 respectively. In women, these were 10521, 3324 and 13846 respectively. There were significant differences between the sexes for the measurements except for StO_2, with all the mean values for the men being twice greater 2)than for the women. In the second study, StO_2 were 8998 in painful side and 9245 in control side with a significance, and the OXHb, deOXHb and THb in the painful side were 24780, 9996 and 32582 respectively. In the control side, these were 23031, 7670 and 30364 respectively. There was a significant difference in deOXHb between two groups. Conclusion : These results provide evidence that sex difference in the Hb oxygenation may exist in the masseter muscle of normal subjects. There may be aggravation of O_2 consumption in the painful masseter site.