We had 2 ways to approach the evaluation criteria

• We should at first establish a strict objective criterion
• Then examine the current products on systematic way

In the beginning we want to model the abutment to be non-indexed (without spline region), then the opinion settles down on modeling it with the hex. No system had been presented with an adequate  knowledge about dimensions. The knowledge about clearances and tolerances in the implant dentistry is so scarce. The best way is to  choose official 3D File or build them from catalogue, where we had followed the latter method.

The most important aspect of he evalatino is the cone angle.

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How we had established the current criteria

• The outer surface will be flat as in the next step we will make the thread. Nevertheless, threads are important to be modelled
• We will choose the closest diameter for each platform to the 4 mm ( mode had 4.3 and 4.8 for the same medium platform so the we will choose the smaller size)
• The availability of the system dimensions will be added as a positive value
• It is the responsibility of the companies to provide the needed data for comparison
• For initial consent about the clearance, we had chosen .1 mm as initial value between the walls of the index region
• The abutment diameter will be same as the maximum diameter at the implant abutment connection or could be same as the maximum diameter of the implant
• When we say initially, we mean that this is the 1^st work
• Initially the space between bottom of the spline region of the implant and the deepest surface of the abutment spline region will be 0.2
• Connecting screw head height will be 2 mm and the thread region diameter will be 1.5 mm for all systems as a base for the models depending on the BIODEM design
• Hole of the abutment for the abutment for the head of the connecting screw head will be 1.7 mm for 0.1 mm clearance at each side
• The distance between the upper surface of the implant and the contact surface between the connecting screw  head and the abutment will be 1mm for all system depending upon the BIODEM design
• The most important design criteria is the cone angle and the implant wall thickness. In the next works, there will be more refined criteria
• The connecting screw head height will be 2mm according to the BIODEM design
• Connecting screw depth will be 3.5 mm and chamfer of 0.5  mm 45-degree angle
• Length of the screw from the screw head will be 1mm shorter than the screw vent of the implant depending upon the BIODEM design with the same chamfer of the implant screw vent
• We hadn’t chosen the model 45 due to the numerical instability and we need to put a new scheme for model selection
• Criteria of evaluation in the next works
• Maximum Implant displacement /maximum abutment displacement = gradient of stiffness
• Center of abutment rotation at lateral force application
• Abutment sinking
• Force distribution when tightens the connecting scarce

in the next figure we had characterize the most important dimension that is needed to be recalled with any comparison