Effect of Double Screw on Abutment Screw Loosening in Single-Implant Prostheses

Purpose: This study was conducted to assess the effect of using a double screw on the prevention of abutment screw loosening. Materials and Methods: Internal connected abutment with a single screw (IS), internal connected abutment with a double screw (ID), external connected abutment with a single screw (ES), and external connected abutment with a double screw (ED) groups were prepared (n = 10 in each group). After 50,000 loading cycles, postload removal torque loss (RTL) percentage was measured. Results: Postload RTL of ID and ED were smaller than those of IS and ES (P = .000 and P = .039, respectively). Conclusion: This study showed that a double screw was more effective in prevention of screw loosening.