Objective To study the effect of different palatal vault shape on the stress distribution of edentulous maxilla surface.Methods Using three-dimensional finite element method(3-D FED),we simulated five bite states,putting five loading conditions on 3-D FED model of maxillary edentulous with three different palatal vault shapes.Results We obtained the stress value and multicolor picture of 3-D FE model.Labial frenal notch zone and alveolar ridge zone were the stress concentration zone of the maxillary edentulous with three different palatal vault shapes under five kinds of loading conditions.The deep palatal vault maxillary edentulous almost had the maximum stress values in labial frenal notch zone,palate zone and alveolar ridge zone,and upper edentulous jaw with palatal torus was the minimum.Conclusion Palatal vault shape can change the stress value of edentulous maxilla surface,but cannot change the stress distribution.Loading condition can change the stress distribution and stress value.

Objective To study the effect of estrogen,recombine human growth hormone and their combinations on residual ridge reduction in osteoporotic rats.Methods Animal models were established by ovariectomy and exodontia on left partial maxillary,then were devided into osteoporosis group and treatment groups;treatment groups were given estrogen and recombine human growth hormone medicial alone and their recombinations.After treatment for 4 and 8 weeks with drugs,the effects of estrogen and recombine human growth hormone on the serum tartrate-resistant acid phosphatase level and bone histomorphometry changes in maxillary were observed in each group. Results ① The serum tartrate-resistant acid phosphatase level was obvionsly lower in ERT group and Er-HGH group than in OP group(P

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Objective: To investigate the effects of estrogen (E 2) on the structure of madible and femur in ovariectomized rats. Methods: 18 femal SD rats were evenly divided into 3 groups:sham-ovariectomized rats (sham-OVX),ovariectonmized rats without E 2 treatment (osteoporosis,OP) and ovariectomized rats with E 2 treatment (E 2).In the group of E 2,E 2 at the dose of 10 ?g/kg was injected into abdominal cavity of the rats every the other 2 days.All rats were sacrificed after 6-week treatment.The madible and femur samples were analyzed by bone histomorphometry with QWin550CW system. Trabecular area (Tb.Ar,%), trabecular width (Tb.Wi,?m) and trabecular seperation (Tb.Sp,?m) were calculated.Result: Tb.Ar(%),Tb.Wi (?m) and Tb.Sp(?m) in the madibles in sham-OVX rats were 29.43?3.12,10.97?1.85 and 27.59?4.21;in OP 19.44?2.24,6.45?1.73 and 42.03?5.46;in E 2 treated 26.81?2.93,9.54?1.22 and 30.98?3.65,respectively.Those in the femus in sham-OVX rats were 24.19?5.53,56.72?10.36 and 132.41?47.69;in OP 12.54?4.32,40.71?8.65 and 208.67?65.39;in E 2 treated 20.08?4.86,51.38?9.07 and 159.42?56.34,respectively.Conclusion: The bone volume decreases more in femur than in madible after ovariectomy in rats.Treament of estrogen can inhibit bone absorbtion in mandible and femur.