Comparison of Customized Abutments Made from Titanium and a Machinable Precious Alloy

Purpose: To investigate the clinical usefulness, a customized abutment produced with the Pd-Ag-In alloy was compared with a customized abutment produced with the conventional titanium alloy for discoloration and mechanical accuracy. Materials and Methods: Discoloration and resistance to corrosion of the Pd-Ag-In alloy were evaluated using chemical solutions. Marginal adaptation of internal-type implants and abutments was compared using 10 titanium abutments and 10 Pd-Ag-In abutments using a surface measuring system. A detorque test was performed on 12 implant-abutment complexes of each control and experimental group to investigate screw joint stability. Cyclic loading simulating a human's mastication movement for 1 year was applied after 30 Ncm initial tightening, and the removal torque was measured using a digital torque gauge. The noninferiority test was conducted to compare the Pd-Ag-In alloy with a titanium abutment with a 10% margin. Results: The Pd-Ag-In alloy had a warm yellow color and displayed stable resistance to discoloration and corrosion, resulting in an advantageous esthetic property. When compared to the titanium alloy, it did not show noninferiority with respect to the gap between the implant and the abutment; the gap was approximately 13.3 μm on average, which was not significantly different from those observed in previous studies. After long-term use, it displayed statistically significant noninferiority in the removal torque value compared to the titanium group. Conclusion: The Pd-Ag-In alloy-based customized abutment had good mechanical properties of the implant-abutment complex as well as a superior esthetic property, and can provide favorable outcomes in anterior implant restoration. Keywords: customized abutment, cyclic loading, dental implants, detorque value, implant-abutment gap