Abstract
Background and Aim: This study aims to evaluate the influence of various retorque timepoints on removal torque amounts in two types of implant-abutment connections.
Methods: In this experimental study, 32 Tixos cylindrical implants were used, divided into four groups based on retorque timepoints using simple randomization: 1- internal hex connection with retorque at 10minutes, 2- internal hex connection with retorque at 10minutes and one month later, 3- Morse taper connection with retorque at 10minutes, and 4- Morse taper connection with retorque at 10minutes and one month later. Abutment screws were tightened using a digital torque meter, followed by retightening after 10 minutes. Subsequent retorquing for Groups 2 and 4 occurred after 85,000 loading cycles. Removal torque measurements were recorded using a digital torque meter. Data was analyzed using SPSS 29 software and the independent samples T-test with Bonferroni correction for multiple comparisons.
Results: The average removal torque in Group1(19.03 ± 0.83) was significantly lower than Group2(21.20 ± 0.98) (p-value < 0.001). However, the average removal torque of Group3(21.60 ± 0.87) and Group4(21.90 ± 1.02) was not statistically significant(p-value=0.186). Regarding the difference between using these two connections, Group 1 had a significantly lower mean removal torque compared to Group 3 (p-value < 0.001), while the difference between Group 2 and Group 4 was not statistically significant (p-value = 0.539).
Conclusion: Current study suggests that abutments with Morse taper connections outperform internal hex connections when retorquing is only applied after 10minutes. Retorquing abutments with internal hex connections one month after cyclic loadings also reduces the settling effect and decreases screw loosening.