Effect of Dynamic Cycles and Abutment Angle on The Screw Stability of Standard and Narrow Implants: An In vitro Study

Abstract

Objective: Screw loosening in implant-supported crowns is a common issue, leading to potential mechanical and biological complications. This study aimed to evaluate the combined influence of cyclic loading, abutment angulation, and implant diameter on screw torque loss in dental implants. Material and Methods: A total of 80 bone-level implants, divided into standard and narrow diameters, underwent cyclic loading protocols. These implants were paired with straight and 15-degree angled abutments. The study assessed the reverse torque values (RTV) before and after loading, with a primary focus on the effects of cyclic loading, abutment angulation, and implant diameter on screw torque loss. Results: Cyclic loading protocols and screw diameter significantly influenced screw torque loss. Standard diameter implants exhibited higher RTV compared to narrow diameter implants. . While the role of abutment angulation was less definitive, narrow diameter implants with angled placements showed a pronounced decrease in RTV. The study also highlighted that even with optimal preload values, a percentage of the initial preload is lost, potentially leading to screw loosening Conclusion: Cyclic loading and screw diameter are pivotal determinants of screw torque loss in dental implants. The study underscores the need for careful consideration of implant diameter and abutment angulation, especially in narrow diameter implants with angled abutments, to ensure optimal implant stability.