The Role of Thread Manufacturing Techniques on Dental Implant Abutment Screw Loosening

Abstract This study investigated the effect of three abutment screw manufacturing methods and modifications in the internal threading process of dental implants on screw loosening. A total of 30 screws were produced, with 10 screws for each manufacturing method. Additionally, 30 dental implants were fabricated and categorized based on their internal threading technique: 15 implants used a cutting tap, referred to as cutting implants (C), and 15 implants used a forming tap, referred to as formed implants (F). Each group of the screws was divided into 2 subsets: one subset was paired with C implants, and the other was paired with F implants. Subsequently, torque loss for each screw was measured before and after a vibration test using a digital torque meter, and a one-way ANOVA and an independent samples t-test (α = 0.05) were used to investigate the significance level of the difference in screw loosening between manufacturing methods. The study found that machined, thread-rolled, and die screws exhibited an average total torque loss of 3.51%, 5.13%, and 7.52% when paired with C implants, and 2.42%, 4.33%, and 6.27% when paired with F implants, respectively. Statistically, the one-way ANOVA and the independent samples t-test revealed a significant effect of the abutment screw type on the total torque loss (P < .05). Moreover, the implant type had a significant effect on the torque loss values before and after the vibration test (P < .05). These findings suggest that screw manufacturing method and internal threading modifications are critical factors in enhancing the mechanical stability of implant components.