Marginal fit and fracture resistance of different yttrium zirconia posterior framework designs
Ahmed Soliman Idris;
Abstract
The effects of different axial coping and finish line thicknesses , as well
as connector designs on the fracture resistance and marginal fit of
yettrium zirconia posterior fixed partial dentures framework was
evaluated in this study.
CAD/CAM cerec in lab system was used to mill thirty bridge frameworks
which are divided into three groups (each of 10 frameworks) according to
finish line and coping thicknesses:
Group 1: (n=10)
Chamfer finish line thickness 0.3mm, coping thickness 0.3mm.
Group 2: (n=10)
Chamfer finish line thickness 0.3mm, coping thickness 0.5mm.
Group 3: (n=10)
Chamfer finish line thickness 0.5mm, coping thickness 0.5mm.
Each group was further subdivided into 2 equal subgroups(n=5)
according to the design of the connector area:
Subgroup A: (5 samples)
The connector is directed occlusaly.
Subgroup B: (5 samples)
The connector is straight.
2 stainless steel models were fabricated. Each model resembled a
prepared lower second premolar and lower second molar with an
edentulous span area for missing lower first molar. The first model is
Summary
114
milled with 0.3mm chamfer finish lines for both abutment, while the
second model is milled with 0.5 mm chamfer finish line for both
abutment.
Both models are duplicated using polyvinyl addition silicon material*
utilizing double mix one step technique . The impressions were poured
with epoxy resin** mixed according to manufacturer instruction and left
to set for 24 hours before separation from the impression.
The epoxy resin models were trimmed and further more duplicated
with polyvinyl addition silicon material utilizing double mix one step and
poured with special cerec stone*** recommended by the manufacturer .
The stone were mixed following the manufacturer instructions then the
impression was poured under vibration. After stone setting the models
were separated from the impression. The excess stone was trimmed, and
the models were now ready for scanning.
The models were scanned by the cerec in-lab system ,then frameworks
designs were adjusted regarding the axial wall thickness and connector
thickness.
The frameworks were milled and sintered in the zyrcomate furnace
Then the veneering procedure was carried out utilizing press on zirconia
technique. Wax pattern resembling the veneering were designed and
milled utilizing CAD/CAM technology then presses using e.max zirpress
ingots.the bridges were placed on the stainless steel model ,and marginal
fit was measured by stereomicroscope. Then the framework were
Summary
115
cemented on the epoxy resin dies using resin cement .finally the
frameworks were fractured using universal testing machine to detect the
fracture resistance.
as connector designs on the fracture resistance and marginal fit of
yettrium zirconia posterior fixed partial dentures framework was
evaluated in this study.
CAD/CAM cerec in lab system was used to mill thirty bridge frameworks
which are divided into three groups (each of 10 frameworks) according to
finish line and coping thicknesses:
Group 1: (n=10)
Chamfer finish line thickness 0.3mm, coping thickness 0.3mm.
Group 2: (n=10)
Chamfer finish line thickness 0.3mm, coping thickness 0.5mm.
Group 3: (n=10)
Chamfer finish line thickness 0.5mm, coping thickness 0.5mm.
Each group was further subdivided into 2 equal subgroups(n=5)
according to the design of the connector area:
Subgroup A: (5 samples)
The connector is directed occlusaly.
Subgroup B: (5 samples)
The connector is straight.
2 stainless steel models were fabricated. Each model resembled a
prepared lower second premolar and lower second molar with an
edentulous span area for missing lower first molar. The first model is
Summary
114
milled with 0.3mm chamfer finish lines for both abutment, while the
second model is milled with 0.5 mm chamfer finish line for both
abutment.
Both models are duplicated using polyvinyl addition silicon material*
utilizing double mix one step technique . The impressions were poured
with epoxy resin** mixed according to manufacturer instruction and left
to set for 24 hours before separation from the impression.
The epoxy resin models were trimmed and further more duplicated
with polyvinyl addition silicon material utilizing double mix one step and
poured with special cerec stone*** recommended by the manufacturer .
The stone were mixed following the manufacturer instructions then the
impression was poured under vibration. After stone setting the models
were separated from the impression. The excess stone was trimmed, and
the models were now ready for scanning.
The models were scanned by the cerec in-lab system ,then frameworks
designs were adjusted regarding the axial wall thickness and connector
thickness.
The frameworks were milled and sintered in the zyrcomate furnace
Then the veneering procedure was carried out utilizing press on zirconia
technique. Wax pattern resembling the veneering were designed and
milled utilizing CAD/CAM technology then presses using e.max zirpress
ingots.the bridges were placed on the stainless steel model ,and marginal
fit was measured by stereomicroscope. Then the framework were
Summary
115
cemented on the epoxy resin dies using resin cement .finally the
frameworks were fractured using universal testing machine to detect the
fracture resistance.
Other data
| Title | Marginal fit and fracture resistance of different yttrium zirconia posterior framework designs | Other Titles | الاحكام الحافى ومقاومه الكسر لهياكل خلفيه مختلفه التصميم مصنعه من يتريم زركونيا | Authors | Ahmed Soliman Idris | Issue Date | 2013 |
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