不同基牙数目附着体义齿对支持组织应力分布的影响

目的探讨铰链式冠外附着体修复末端游离缺损时,不同基牙数目对支持组织应力分布的影响。方法以铰链式附着体为固位体,修复右下第二磨牙游离缺损,分别制作以第一磨牙为基牙的单基牙附着体义齿的三维光弹模型和以第一磨牙及第二前磨牙为基牙的双基牙附着体义齿的三维光弹模型。采用光弹性应力分析法,定性分析不同基牙数目时,该附着体义齿对基牙牙周支持组织应力分布的影响。结果附着体义齿在正中咬合情况下,单基牙时,在该附着体义齿的缺牙区牙槽骨内、基牙的远中根尖和近中根尖处,可见应力集中;双基牙时,得到的结果相似。结论用该附着体修复第二磨牙末端游离缺损时,在正中咬合情况下,基牙数目对支持组织的应力分布无明显影响,提示临床可采用单基牙;在正中咬合情况下,基牙与牙槽嵴黏膜应力分布均匀,提示该附着体适用于基牙条件稍差、而牙槽嵴黏膜条件较好的患者。

Effect of stress distribution of support tissues using attachment prostheses with different number of abutment

PURPOSE: The purpose is to evaluate the effect of the stress distribution of support tissues when using the hinge extracoronal attachment for distal-extension prosthesis with different number of abutment. METHODS: Hinge extracoronal attachment was used for retention in distal-extension prosthesis. The 3-D photoelastic models of attachment of the denture of single abutment with the first molar or double abutments with the first molar and the second premolar were fabricated. Photoelastic analysis was adopted to compare the stress patterns generated around the support tissues with different number of abutment. RESULTS: Under central occlusion, most stress of the attachment of the denture with single abutment was concentrated at the edentulous ridge, the distal and mesial apex of the abutment. The results were similar with double abutments. CONCLUSIONS: In choosing attachment prostheses to restore the second molar distal-extension defects, we can choose only one tooth as abutment. The number of the abutment has no significant effect on the stress distribution in the supporting tissue under central occlusion,and there is an evenly stress distribution at the edentulous ridge and in the abutment.The attachment is suitable for cases with better alveolar membrane without high demand for abutment teeth.Supported by Development Fund of Science and Technology of Shanghai Municipality(Grant No. 004119075).