الفهرس 
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Abstract
Abstract
Purpose: This study evaluates the marginal adaptation, fracture resistance and
deflection in short and long spans dental fixed prosthesis.
Materials and methods: 140 fabricated interim FPD were divided into two main
groups: group I: short-span FPD (n=70) & group II: long-span FPD (n=70). Each
group was subdivided into seven subgroups (n=10) for each according to interim
materials: Subgroup A: CAD-CAM composite blocks, Subgroup B: Chemicalcured
acrylic resin material, as control, Subgroup C: zirconia powder reinforced
acrylic resin (experimental), Subgroup D: Chemical-cured composite resin,
Subgroup E: Dual-cured composite resin, Subgroup F: Light cured composite resin
reinforced with polyethylene fibers & Subgroup G: Light cured composite resin
reinforced with glass fibers. Marginal adaptation was measured using USB Digital
microscope. Fracture resistance and deflection values were evaluated by three point
bending test using ”Instron testing machine”.
Results: Long-span FPD recorded higher marginal gap than short-span FPD
(mean: 47.88 μm vs 43.78 μm, p<0.001). When testing the marginal gaps of
different tested materials of the prepared interim FPDs of short and long span FPD
groups, the highest mean value was recorded for zirconia powder reinforced acrylic
resin (50.48 μm & 64.26 μm) respectively and the lowest mean value was recorded
for polyethylene fiber reinforced composite ”Construct®” (33.99 μm & 30.69 μm)
respectively. Long-span FPD recorded higher deflection than short-span FPD
(mean: 5.18 mm vs 3.49 mm, p<0.001).When testing deflection with short and long
span FPD groups, the highest mean value was recorded for polyethylene fiber
reinforced composite ”Construct®” (9.80 mm & 7.18 mm) respectively, while the
lowest deflection mean value was recorded for dual-cured composite resin
”TemSpan TM” (2.12 mm) for short span FPD group. But the lowest deflection
mean value was recorded for CAD-CAM composite blocks ”VITA-CAD Temp”
(3.39 mm) for long span FPD group. Short-span FPD recorded higher fracture
resistance than long-span FPD (mean: 65.18 Mpa vs 52.42 Mpa, p<0.05). When
testing fracture resistance with short span FPD group, the highest fracture
resistance mean value was recorded for zirconia powder reinforced acrylic resin
(141.7 Mpa) and lowest mean value was recorded for chemical-cured composite
resin ”ProtempTM4” (20.86 Mpa). When testing fracture resistance with long span
FPD group, the highest mean value was recorded for CAD-CAM composite blocks
”VITA-CAD Temp” (102.1 Mpa) and the lowest mean value was recorded for
chemical-cured composite resin ”ProtempTM4” (20.33 Mpa).