الفهرس 
ental implant complications
Study design: The experimental trial will be adopted for this work.Only 14 pages are availabe for public view
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Abstract
Summary
Dental implant restoration has been widely accepted as one of the
treatment modalities to replace missing teeth and to restore human
masticatory function.
However, implants can fail and fracture, posing a major problem for
both patient and the clinician.
One of the key factor for the long term success of implant treatment is
the passively of fit between the superstructure and the implant. However, in clinical situations, it is almost impossible to achieve a completely passive fit
of the prosthetic framework to the implant abutments, especially in multiple
splinted implant restorations.
The purpose of this in-vitro study was to evaluate the effect of internal
hex height and gingival height on marginal fit of implant abutment
connection before and after dynamic cyclic loading using scanning electron
microscope (SEM).
Eighty stock straight abutments with different hex height and gingival
height were divided into 4 equal groups (N=20): twenty each according to
height of internal hexagon and gingival height of abutment itself. group I:
abutment with.1 mm internal hexagon height and 1mm gingival height,
group II: abutment with 0.6 mm internal hexagon height and 1mm gingival height, group III: abutment with 0.6mm internal hexagon height and 3mm gingival height, group IV: abutment with 0.6mm internal hexagon height and
4mm gingival height. Each fixture was vertically placed in the center of
epoxy resin block using modified dental surveyor and blocks were .made
from specific stainless steel mold blocks and designed to fit into recesses in a stainless steel form (20 mm long, 20 mm wide, and 10 mm thick). At the center of the mold surface a small indicator with the same width of the implant mount was made. For each selected abutment with different internal
hex height and gingival height metal tube was fabricated to fit accurately on
abutment .The samples were subjected to eccentric cyclic loading (at
distance 2-3mm) away from the centre of abutment at three different
intervals 10000, 100000,500000cycles.Marginal fit was evaluated before and
after each cycles by measuring microgap size in( µm) using scanning
electron microscope (SEM) with a magnification 700x.The values of
microgap size in µm before and after cyclic loading were analyzed using
Anova and paired t student test followed by tukey’s test post hoc test.
After cyclic loading the microgap size was measured in all groups and
high value was recorded to GIV abutment with 0,06 internal hex height and
4mm gingival height (20.966±2.795) while minimum value recorded to GI
abutment with 1mm internal hex height and 1mm gingival height (
8.400±2.166).One way ANOVA showed significanct effect upon marginal
fit between the four groups.