Objective:To build a three-dimensional finite element model of child temporomandibular joint including the mandible with chincap

and provide a basic condition for the study of the effects of chincap on the stress distribution of the base of mandible.Methods:The model was constructed from a child who accepted the treatment of chincap by ANSYS 5.6

using the reconstructive technique of spiral CT in combination with the three-dimensional finite element.The model consisted of 20045 bricks and 4442 nodes.On the model

mandible retraction was simulated under the different traction which included the different directions and magnitudes.Results:Three-dimensional model of the `Temporomandibular joint-mandible-chincap system of child’ was established

which was better suited for the actual and practical situation of chincap in clinic

and the loading point and the different directions and magnitudes were determined by clinical application.Mechanical changes of various parts of the model in different working conditions could be simulated by means of adding different material properties and boundary conditions.Conclusion:The established model could be used for the study of stress distribution of chincap applying simulation.