Comparison of Abutment Screw Loosening in Titanium Versus Zirconia Implants: An In Vitro Study

Abutment screw loosening is a common complication in implant-based prostheses. Given the importance of esthetics in anterior regions, zirconia implants and abutments have been introduced. This study aims to compare the extent of abutment screw loosening between zirconia and titanium implants to determine the best treatment option. This in vitro study assessed abutment screw loosening in titanium and zirconia implants. Ten zirconia dental implant fixtures (10 mm in length, 4.3 mm in diameter) with 10 zirconia abutments and titanium screws were allocated in one group, and 10 titanium implant fixtures of the same dimensions with 10 titanium abutments and titanium screws were allocated to the other group. The abutment screws were tightened to a torque of 35 N/cm using a torque meter and placed in resin blocks. The center of the resin block then underwent a compressive force of 75 N and 12 400 cycles and a frequency of 75 cycles per minute. Furthermore, the removal torque value of each screw was measured. The data on screw loosening forces were analyzed and compared using a t test with a significance level set at 0.05. The average removal torque for titanium implants was 21.53 N/cm, whereas for zirconia implants, it was 18.46 N/cm. A t test comparison showed that titanium implants had a significantly higher removal torque value than zirconia implants (p < .001). In laboratory conditions, titanium implants exhibit significantly higher removal torque values than zirconia implants, suggesting they may offer better stability in similar clinical settings.