الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 169 |  |  |
| | | from | 169 | | |
Abstract
Restoration of teeth after endodontic treatment is an integral part of
restorative practice in dentistry. As these teeth are affected by a higher risk
of biomechanical failure compared to vital ones, a plethora of articles have
been written in the dental literature regarding the prosthodontic management
of endodontically treated teeth. Many of these papers have discussed
techniques of fabricating posts and cores, whereas others presented clinical
and laboratory data that help to answer questions regarding the best
prosthodontic treatment for these teeth.
The purpose of this study was to evaluate the influence of Ferrule
Design, Post Type and Functional Loading on the Fracture resistance and
Coronal Leakage of Endodontically Treated Maxillary Premolars.
One hundred intact bifurcated maxillary first premolars were selected
for the study. selected teeth were randomly divided into three main groups;
two test groups and one control group. Test samples were prepared to
receive post, core and coronal coverage and were assigned in two groups (U
& N) according to the remaining amount of tooth structure. Teeth of group
U (n = 40) were prepared to provide a ferrule of 1.5mm uniform height,
while for group N (n = 40) further teeth reduction was performed to provide
a ferrule of non-uniform height (1.5mm buccal and palatal, 0.5mm
proximal). According to post type, whether ready-made or individually
formed FRC post, each test group was divided in 2 equal subgroups (R & I).
Control samples, group A (n = 20) were prepared for coronal coverage, no
posts were used and the prepared teeth were intact except for endodontic
access openings.
According to the loading condition, being a crown (C) or a bridge (B)
abutment, premolars of the control group and the test subgroups were
divided in two equal divisions (n = 10).
Polyethylene core formers were used to form standard composite
cores, while silicon molds were used to Shape the wax patterns of the
suprastructures. All posts and suprastructures were cemented using dual
cured composite resin cement. Then the specimens were subjected to
thermal cycling and dynamic loading before testing.
Half the specimens were tested for fracture strength evaluation in a
Universal Testing Machine by the application of an oblique load at an angle
of 30º degree to the long axis of the tooth. The other half was assessed for
coronal micro-leakage using the linear dye penetration test.
Statistical analysis of the results revealed that functional loading,
post type and the interaction between the three variables had a statistically
significant effect on the fracture resistance, while the ferrule design didn’t
influence the results. In terms of coronal leakage, none of the tested
variables significantly affected the results. There was a non-statistically
significant negative (inverse) correlation between fracture strength and
leakage scores.