纤维桩核结构长度影响因素的文献回顾

Factors affecting the length of fiber post and core structure:a literature review

桩的根内长度与冠部长度应存在一个理想的平衡点。一些学者提倡在不破坏根尖封闭的前提下桩应该尽可能长。另一些学者认为桩长应该大于冠长或与根长成一定比例。从半个世纪前开始,一般认为桩长应为牙根长度的2/3~3/4。这些学说大都强调依靠桩的长度来增加冠部修复体的固位力。然而,近年来口腔材料学的发展日新月异,纤维桩树脂核代替金属桩核,树脂类水门汀代替传统的磷酸锌、玻璃离子水门汀,桩的应力分布和固位力得到改良。因此,有理由认为对于粘结力强的纤维桩,桩长应在保持足够固位力的前提下最小化。牙本质肩领高度、桩在根内长度、牙槽骨内桩长度、预备体高度、核的长度和桩在骨外的长度这6个影响因素在维持桩核力学平衡中有重要意义。本文归纳纤维桩的影响因素,结合文献进行综述。

An ideal balance between the post length within root and the coronal extension should exist.Some theories advocated the use of the longest post as possible as the apical seal is not disturbed.Others advocated that the post should be longer than the crown or that the post should be a certain fraction of the length of the root.The conventional post length has been equal to2/3?3/4of the root length from half a century ago.Most of these theories have emphasized the post length in order to achieve sufficient retention and rigidity for coronal restoration.However,dental materials are evolving.With the use of fiber post and resin cement,stress distribution and post retention are improved over conventional metal post and zinc phosphate or glass?ionomer cement.Therefore,with improved bonding strength of fiber post,the post length within root should be minimized to maintain sufficient coronal rigidity.Factors affecting fracture resistance balance of a post?and?core system include the amount of Ferrule height(FH),Post length in root(PLIR),Post length in bone(PLIB),Abutment height(AH),Core length(CL)and Post length out of bone(PLOB).In view of the factors mentioned above,this paper investigated the mechanical factorsin a post?and?core system with literature review.