Objective To investigate and analysis the situation of malocclusion of 49 skulls of ancient resident in Xinjiang, and discuss the history evolution and the pathologic mechanism of malocclusion. Methods The investigation was carried out based on the standard of individual normal occlusion. Results Among the group of 49 skulls, the morbility rate of malocclusion was 30. 61% ; in Angle's classification of malocclution, class I was the most (73. 33%); in Mao's classification of malocclution, class I was also the most (33. 33%). Conclusion The morbility rate of malocclusion of resident in bronze age is lower than that of modern resident and nearer ages resident. There is a close releationship between the human food construction and the pathogenesis of malocclution.

The finite element method was used for simulating the mechanical performance and fatigue safety of three different structures of Nitinol stent. According to the actual situation, after proposing reasonable assumptions and simplification, the geometry model and finite element model establishment, material mode selection and boundary condition setting are completed. The strain and fatigue life of different stent edges wide (omega) or strut angle (theta) are computed. The result can provide a valuable reference for the optimal design of stent.
Alloys ; Finite Element Analysis ; Prosthesis Design ; Stents

The finite element method was used for simulating the mechanical performance and fatigue safety of three different structures of Nitinol stent. According to the actual situation, after proposing reasonable assumptions and simplification, the geometry model and finite element model establishment, material mode selection and boundary condition setting are completed. The strain and fatigue life of different stent edges wide (ω) or strut angle (q) are computed. The result can provide a valuable reference for the optimal design of stent.