الفهرس 
Review of LiteratureOnly 14 pages are availabe for public view
 |  | from | 98 |  |  |
| | | from | 98 | | |
Abstract
Completely edentulous Mandibular cast was prototyped using 3D printing technology.
This was done via scanning an educational model and designing an STL file including all the details required; implants beds, mucosal space for mucosa simulation and vertical slots for strain gauges which were 1mm distal and labial to each implant.
Mucosa simulation was planned to mimic the viscoelasticity of the fibrous mucoperiostium by prototyping a mucosa simulator over the scanned model after removing 2 mm space over the crest of the ridge and making all around shelf for stabilization of the removable mucosa.
Printing was ordered and mucosa simulation was done by an addition silicon rubber base utilizing the printed mucsimulator. Four dummy implants were placed in their beds.
Multiunits abutments were placed above implants, then plastic abutments were placed where overdenture materials were fabricated.
This study will be divided into 2 groups according to the type of over denture materials:
group (1): Zirconia bar implant retained mandibular overdenture.
group (2): conventional acrylic resin with chrome cobalt bar implant retained mandibular overdenture.
Strain gauges were supplied with fully encapsulated grid and attached wires. The wire used for strain gauges were insulated by a packing material.
Before securing the mucosa simulator in its space and screwing the abutments. Strain gauges were installed at the distal and labial aspect of last 2 bilateral implants.
A T-shaped load applicator was made to fit on the denture teeth bilaterally between the central fossa of lower first molars.
After fifteen minutes the same load was applied unilaterally on the right side to represent the working side at the first molar using I bar shaped load applicator.
After another fifteen minutes oblique load was applied unilaterally on the right side to represent the working side at the first molar using I bar shaped load applicator.
Micro-stains were recorded at each site of the strain gauges with enough time elapsed between each testing. A four channel strain meter was used to assess the strains induced by each applied load. The applied load started from zero up to 100N.
The same steps were followed with each type of the overdentures after connecting it to the implants.
All data were collected and tabulated, one- way ANOVA analysis at a significant level P< 0.05 was performed by Statistical Package for Social Science (SPSS) version 22.
The results obtained from this study revealed significant difference between the zirconia bar and the conventional acrylic resin with cobalt chromium bar on the average stresses falling on the implants.
And there is a significant difference between the zirconia bar and the conventional acrylic resin with cobalt chromium bar on the average stresses falling on four implants and there is significant difference between the loaded and the non-loaded side.
The average stresses falling on the implants attached the zirconia bar was less than the average stresses falling on the implants attached the cobalt chromium bar.