不同载荷下中间种植体基牙天然牙-种植体联合桥基牙应力分布及位移

目的：揭示在不同载荷下中间种植体基牙天然牙-种植体联合桥基牙应力分布及位移规律，指导临床义齿制作。 方法：用三维有限元法研究天然牙及中间种植体受力后的应力分布特点及位移规律。 结果：4种载荷下种植体最大应力值均是天然牙的4~5倍；集中垂直载荷下种植体最大应力值大约是分散垂直载荷下的2倍；斜向集中载荷与斜向分散载荷下种植体最大应力值无明显差异，大约是分散垂直载荷下种植体最大应力值的3倍；分散载荷下天然牙最大应力值均较集中载荷时低。牙合龈向种植体最大位移值远小于天然牙|3位移值，在颊舌向和近远中向两者位移差值较小。 结论：颊舌向力是破坏修复体的主要因素，应降低牙尖斜度；集中载荷比分散载荷破坏作用大，应消除咬合高点，建立分布均匀的多点咬合接触。这种固定桥是可行的。

Stress distribution and displacement of abutment of middle implant-natural teeth fixed bridge under different loading

Objective To study stress distribution and displacement of abutment of middle implant-natural teeth fixed bridge under different loading. Methods The stress distribution and displacement of abutment were studied and analyzed by means of three-dimensional finite element when different loading was applied. Results The biggest stress of middle implant was 4-5 times as big as that of natural teeth. Under concentrated vertical loading, the biggest stress of implant was about 2 times higher than that under dispersed vertical loading. There was no significant difference of biggest stress on the implant between concentrated oblique loading and dispersed oblique loading. The biggest stress of implant under oblique loading was 3 times as big as that under dispersed vertical loading. The biggest stress of natural teeth under dispersed loading was lower than that under concentrated loading. The maximum displacement of implant in occlusal-gum direction was great lower than that of natural teeth. Both in buccal-lingual direction and medial-distal direction, the displacement of implant were about equal to that of natural teeth. Conclusion The oblique loading is the main force to destroy the middle implant-natural teeth fixed bridge. The lean of cusp should be reduced .The abnormally high occlusal points should be deleted. The bite points should be well distributed. The fixed bridge is feasible.