Mechanical Testing of Inclusive Custom Abutments

Superior Materials
The high strength of Inclusive Titanium Abutments begins with material selection. The titanium abutments are precisely machined from ASTM grade 23 alloy titanium. Grade 23 titanium has a minimum yield strength of 760 MPa before plastic deformation occurs, compared to the 480 MPa minimum yield strength of grade 4 commercially pure titanium used for many abutments. Glidewell Laboratories uses titanium abutment blanks that are manufactured on Swiss-style CNC automatic lathes utilized throughout the implant industry.

For ceramic materials such as zirconia, flexural strength is used to measure the strength of the material in bending. Inclusive All-Zirconia Abutments are machined from high-strength zirconia with a flexural strength of 1500 MPa. Zirconia with Titanium Insert Abutments include a metal insert and provide a titanium-to-titanium abutment-implant interface. The insert is permanently cemented with 3M ESPE RelyX (St. Paul, MN) to the zirconia section in the lab. Zirconia abutment blanks are manufactured on five-axis CNC mills. The entire manufacturing process is tightly controlled, from material issue to final inspection, to ensure quality and consistency.

Rigorous Testing
Abutment-to-implant compatibility requires manufacturing the prosthetic components to very close tolerances. Further, the mechanical function and performance of the abutment/ implant assembly should be determined by fatigue testing that approximates actual-use conditions. Fatigue-strength testing based on the ISO 14801 protocol was conducted on the implant/abutment assemblies to determine fatigue strength. Fatigue-strength testing was performed at an independent laboratory on both Inclusive Titanium and All-Zirconia Custom Implant Abutments for every implant system offered.

The fatigue strength is the maximum force that the assembly can withstand after cyclical loading at a frequency of 14Hz. Testing is typically done on the smallest, and therefore the weakest, diameter implant. In this test, 3.5 mm (NP) Inclusive All-Zirconia Abutments had a fatigue strength of 289 - 333 N after 5 million cycles. To put it in perspective, the bite forces in the anterior region where zirconia would be primarily indicated have been reported in the range of 109 to 299N.1,2