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Part 2.
2.1 Introduction.
Posts and cores are commonly used for the restoration of endodontically
treated teeth when these teeth have suffered coronal damage. The loosening of the
post and the core or the fracture of the remaining dentin are frequently observed
problems. According to Gher ‘s clinical survey (1987) out of 100 fractured teeth
92 had been previously restored. The failure of the restored teeth was related to
post and core designs.
Over the last three decades a lot of literature on the stress-strain analysis of
the post-core restored endodontically treated teeth has been published. The
publications on the effect of posts on stress distribution are controversial. Some
researches promoted use of posts by claiming that they served to reinforce teeth.
Other researches reported that the placement of the post could create stress that
leads to root fracture in use.
It is known that endodontically treated teeth are generally weaker because of
dental structure loss, cavities, filling preparation and root canal instrumentation. It
is also important to point out that dentin moisture decrease would lower their
strength properties making them more susceptible to fractures (Helfer, Melnick &
Schilder, 1972). Therefore, special care is needed when selecting the most
efficient way to restore them. Dentistry has searched for an ideal approach to
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