Amir Saad Thesis final revision 03x - IUPUI

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cores. When nonvital teeth were restored with cast post and cores in resorbed bone (5
mm below the cementoenamel junction), there was no significant difference in
fracture resistance between cast post and core restorations versus glass fiber posts
with composite resin core build-up. It was found that increasing the post width does
not increase post retention significantly. 63, 85 Longer posts demonstrated more
retention than shorter ones. 63 It was also found that short posts transmit greater lateral
forces to the remaining root structure compared with longer posts. 86
Fiber posts have an elastic modulus (E = 20 GPa) similar to that of dentin (18
GPa) when compared with cast and prefabricated metallic posts (E = 200 GPa). Thus,
stresses along the remaining tooth structure are distributed instead of concentrated, 7,
87-92 which would explain the lack of significant root fractures. 7 FiberFill (Pentron,
Wallingford, CT) (Glass fiber obturator- post with gutta percha tip) demonstrated
significantly higher fracture resistance values compared with conventional cast post
and core, FiberKor (glass fiber post), and metal prefabricated posts. 93 Prefabricated
metal posts and cast post and cores have been used for a long time and are still being
used as the standard treatment. It is found they increase the risks of root fractures. 6
Although fiber posts are found to be affected by moisture, modulus or elasticity and
flexural strength levels exceeded the strength necessary to avoid fracture of the post
during function. 6
In a survey made in the late 1980s, it was estimated that around 25 percent of
all prosthetically restored teeth are nonvital and endodontically treated before
prosthetic restoration. 94 Questionnaire surveys of dentists in the US, Sweden,
Germany, and Switzerland have shown disagreements about prosthetic treatment of
endodontically treated teeth. Surveys included but were not limited to current