OBJECTIVETo study the role of Ca2+ overload and energy metabolism in mitochondria in masticatory muscle dysfunctional induced by occlusal trauma.

METHODSMitochondrial Ca2+ contents were measured with atomic emission spectrophotometer. Mitochondrial ATP and ADP contents were measured with high performance liquid chromatography.

RESULTS(1) Mitochondrial Ca2+ contents of masseter muscle ipsilateral to metal splint in ten and twenty days' experimental groups and that contralateral to metal splint in twenty days' experimental group increased significantly (P < 0.05). (2) Mitochondrial ATP contents of masseter muscle ipsilateral to metal splint in experimental groups were higher than that in control groups and contralateral to metal splint after twenty days. (3) Mitochondrial Ca2+ contents of masseter muscle ipsilateral to metal splint were significantly negatively correlated to the mitochondrial ATP contents (r = -0.780, P < 0.05).

CONCLUSIONCa2+ overload in mitochondria depresses ATP production, which results in energy metabolism disorder in masticatory muscle cells. It may play an important role in the mechanism that occlusal trauma results in masticatory muscle dysfunction.