الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 139 |  |  |
| | | from | 139 | | |
Abstract
Four intact human teeth (two maxillary first premolars and two maxillary first molars), the specimens were divided into three groups according to the bridge design. In order to evaluate endocrown retained bridge, it was compared with the conventional full coverage 3-unit bridge.
These three main groups were then subdivided into two subgroups according to the material type. IPS e.max press, and Bio HPP for 2press material.
Our main concern was studying the fracture resistance of both materials with different preparation designs.
For standardization the teeth were prepared using Computer Numerical Control machine, then the prepared teeth were mounted in the acrylic cast using paralleling device, Optical impression was taken and 3D printed models were fabricated (14 models for each design).
In order to standardize the dimensions of the restorations throughout all the samples, a CAD/CAM wax models were designed and milled, Then the restorations were all made by pressing technique.
The specimens then underwent cyclic loading. The load used was 50N and was applied at an right angle just above the pontic from the occlusal surface for 75,000 cycles
The fracture load of all the specimens was measured after continuous compressive load till failure occurred in a Universal Testing Machine.
Data analysis was performed in several steps. Initially, descriptive statistics for each group results. Two-way analysis of variance ANOVA test of significance was done for comparing variables (material group and restoration type) affecting mean values. One way ANOVA followed by pair-wise Tukey’s post-hoc tests were performed to detect significance between subgroups.Pair-wise student t-test was performed to detect interaction between variables of significant effect. Statistical analysis was performed using Aasistat 7.6 statistics software for Windows (Campina Grande, Paraiba state, Brazil). P values ≤ 0.05 are considered to be statistically significant in all tests.