T. Kanayama et al., Comparison of phosphocreatine concentration in the human masseter and medial pterygoid muscles by P-31-CSI, J ORAL REH, 28(11), 2001, pp. 1075-1079
The aim of this study is to compare phosphocreatine (PCr) concentrations of
human masseter and medial pterygoid muscles by a recently developed locali
zed magnetic resonance spectroscopy (MRS) method, chemical shift imaging (C
SI). The characteristic spectra of phosphorous metabolites including PCr an
d P-ATP from the superficial part of the masseter (SM) and the deep part of
the masseter (DM) and the medial pterygoid muscles (MPt) from 11 volunteer
s, 20-27-year-old were obtained. The study clearly demonstrated higher PCr/
beta -ATP in the SM and MPt than in the DM both in mean values (P<0.01) and
in individual subjects. The results indicate that SM and MPt are power pro
ducers. There were no significant differences in the mean values of the PCr
/<beta>-ATP ratios in SM and MPt, however, the PCr/beta -ATP ratios varied
individually and the subjects could be divided into three distinct groups:
values of MPt higher than SM (group A, 4 subjects); values of MPt almost eq
ual to SM (group B, 3 subjects); and values of MPt lower than SM (group C,
4 subjects). There appears to be a close relationship between the PCr conte
nt as determined in the groups here and occlusal guidance.