الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
A persistant problem in clinical dentistry is associated with fractures occurring in endo-treated
teeth, since it was confirmed that there is alteration in physical properties of a tooth that has
undergone pulp removal which is complicated by substantial loss of coronal and radical tooth
structure. Therefore the remaining coronal portion is a primary factor that affects decision making
in regard to type of required restoration.
For many decades, insertion of a full coverage restoration was the only possible option in order to
overcome the assumed brittleness and structural weakness of endo-treated teeth.
Nowadays there are several restorative options beside full coverage as the insertion of a fiber
reinforced composite (FRC) post and core build up. fibre-based posts are essentially composite
materials. They are composed of fibres of carbon or silica surrounded by a matrix of polymer resin,
usually an epoxy resin. A wide variety of posts are available and include parallel-sided,
tapered,smooth and serrated forms. silica-fibre posts which are translucent and more tooth
coloured. These posts are also called glass-fibre and quartz- fibre. Despite efforts to reinforce
endodontically treated teeth with internal post and cores, tooth fracture continues to occur.
That’s why the availability of 2 mm of coronal tooth structure between the crown preparation
shoulder and tooth/core junction was found to enhance fracture resistance. This 2 mm of tooth
structure will provide a ferrule effect with the artificial crown that should prevent fracture of
the root, fracture of the post, and dislodgement of the post. It appears that this extension of
coronal tooth structure provides the greatest influence in terms of resistance and retention form
for a crown.