Replica technique remain most commonly used technique for
measuring the marginal fit in the medical literature, the silicone
rubber addition is considered most accurate and least changing
dimensions.
Aim of study to compare the accuracy and simpl
icity of traditional
replica technique and modified replica technique to measure
marginal fit of zirconium posterior bridges manufactured by
CAD\CAM. After removal of first lower molar from TYPODENT
(Frasco, Tettnang, Germany), the second lower molar and premolar
neighboring were prepared commensurate with full ceramic
restoration. Final impression of this bridge was taken by silicone
rubber addition (Zhermack Elite HD+) with the aid of custom tray.
The impression was condensed with amalgam to make the main
metal cast. Fifteen custom acrylic resin trays were used for fabricate
fifteen impressions of main metal cast that were used for fabricate
15 zirconium bridges by CAD\CAM technique According to the
manufacturer's instructions. Tow rubber thicknesses were taken for
the marginal fit of each bridge over its cast gypsum by used light
silicone rubber addition. Then the first rubber thickness was treated
by developed replica technique to form the Group (A) of the study
and the second rubber thickness was treated by replica technique to
form the group (B) of the study. Depending on T-test, no significant
difference between two techniques was detected. We conclude that
developed replica technique reliable technique to study and measure the marginal gap of bridge and crown, and it is statistically more accurate than the traditional technique.
Recent development in dental materials had led to the fabrication of metal free fixed
prosthodontics to improve the mechanical and aesthetic properties to restore posterior teeth
depending on many techniques, therefore came the propose of this stud
y to compare the
marginal fit of Zirconia bridges made by CAD/CAM and Slip-Cast techniques.
30 Bridges were fabricated to restore missing first lower molar, they were divided
into two groups (15 CAD\CAM, 15 Slip-Cast). The marginal fit was evaluated by
measuring the thickness of light body silicone that made using Replica technique.
Depending on T-test, the mean marginal discrepancy for CAD/CAM groups was
13.92μ and 11.30μ for Slip-Cast techniques.
Therefore, it was concluded that the marginal fit of Slip-Cast techniques was
significantly better than CAD/CAM techniques.
It was recently noted that there are
serious trials to develop dental materials used in the prosthodontics.
As a result of this development, some veneering ceramic systems
used in metal-ceramic crowns have been appeared. In view of the
major impo
rtance of marginal fit and its role in the success of
restoration it must be a study and evaluation of marginal fit for these
modern systems.
This research aimed to comparasion of marginal fit for metal ceramic
crowns using two types of veneering ceramic.
Porcelain Laminate Veneers have shown promising results recently
when used as an alternative to metal ceramic restorations for the
anterior teeth. Long-term success for any restoration depends on the
marginal fit, because marginal gaps increase pl
aque accumulation
and causing periodontitis. The aim of this study was to Asses
marginal fit changes according to were curing the bond agent before
or after cementation.