對於嚴重的齟齒形式，常需要將原有牙齒本體予以部分移除，再行填充入新的填補材料，以重新恢復牙齒原有的功能，然而這種復形法必然有相異材料之鄰接界面存在，亦即將可能於界面尖端處發生局部的應力值過大現象，這是難以避免的。本研究將針對此種填補法中，數處可能發生異相材料交接界面之位置，依照其界面型態，分別以楔形（wedge）及全相（junction）結構來加以模擬，藉由Muskhelishvili複變函數理論運用於多種材料楔形結構之複變函數關係式，來分析各位置之應力奇異性。
本論文將從固定牙齒本體的材料性質，而經由改變填補材料之材料性質著手，並設定所有材料均為等向性，分別變化填補物之楊氏係數及蒲松氏比，而討論在與牙齒本體各個不同角度組合之下，其可能發生的應力奇異性階數，將其畫成奇異性階數—角度分佈圖，找出最小奇異性階數所對應之角度，希冀提供移除窩洞幾何外型之設計參考。
除了牙齒本體幾處可能發生材料不連續之界面外，另外探討了因為部分填補材料可能因為收縮現象而無法完全與牙齒本體密接，而在界面之處發生之脫離（debonding）現象，針對這種案例，本文係以不同於前述之不完全接合全相（debonding junction）結構來模擬，同樣也可以找出各角度組合所對應之應力奇異性階數。

This paper presents the singular stress analysis near the apex of a structure formed from dental restoration of premolar class Ⅱ cavity. Based on the elasticity theory, the stresses may go infinity at the junctions of different materials (e.g. dentine, enamel, restoration materials). It will cause material separation and then totally fracture. In order to get rid of the failure probability, the degree of stress concentration has to be reduced. The stress singularity order and the stress intensity factor are two parameters, which are often used in the fracture analysis. The objective of this paper is to find the conditions such that non-singular stress fields are possible.
Three positions in the restoration structure are of interested. They are the tips of interface between (1) enamel and restoration, (2) dentine and restoration, and (3) enamel, dentine and restoration. In the last two cases, the restoration mat be bonded or debonded to enamel or dentine. After employing the Kolosov-Muskhelishvili complex functions together with eigenfunction expansion method, the singularity orders are computed theoretically. The weak stress singularity conditions can be sought by proper selecting the cutting angles or the restoration materials.

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