OBJECTIVETo measure the muscle pressure exerted on the deciduous normal occlusion and to explore the relationship between the denture,occlusion, skeleton and muscle pressure.

METHODSThirty volunteers of deciduous normal occlusion were included in the study. The muscle pressure of natural head posture (NHP) was measured at rest and during swallowing by a PC real-time measuring system and the data were analyzed by statistical software SAS.

RESULTThe forces from lips, cheeks and tongue at rest were 0 approximate, equals 1.47 g/cm(2), while the pressure were increased to 9.60 approximate, equals 20.13 g/cm(2) during swallowing. The lip pressure was higher than the lingual side but there was no statistical difference at rest. The boys had higher pressure than girls,but there was also no statistical difference at rest. The pressure of normal occlusion was related to sex at the position of the upper labial incisor and the side of the dental arch during swallowing. The pressure of both sides of the dental arch increased significantly during swallowing.

CONCLUSIONThe deciduous dentition is in a state of dynamic equilibrium. This equilibrium may result in a special facial morphology.