Purpose: The aim of this study was to examine and compare the mechanical success of customized computer aided design and manufacturing (CAD-CAM) and prefabricated abutments and screws before and after cyclic loading, through measuring removal torque values. Materials And Methods: The study was performed in accordance with ISO 14801:2016 standarts. Twenty eight dental implants with identical charecteristics were divided into two equal groups. The control group comprised of prefabricated abutments and screws, while the study group included customized CAD-CAM abutments and screws. Removal torque values (RTV) were measured before and after 50.000 and 1 million cyclic loading in both groups. Additionally, to evaluate the screw fatigue performance, they were retightened with 30N torque and RTV measurements were repeated. The data were analyzed using ANOVA, Newman Keuls test and paired t-test. Results: No significant difference was observed in RTVs before cylic loading within each group. However, the RTV's measured before cyclic loading were found to be significantly lower in the study group compared to the control group. Both groups exhibited a significant decrease in RTV after cylic loading. The RTV of the study group was significantly lower than the control group especially after 1 million cycles. No significant difference was found in the screw fatigue performance between two groups. Conclusion: The significantly lower RTVs of customized CAD-CAM abutments and screws before and after cylic loading have raised questions about their effectiveness and widespread use. This study underscores the necessity for further clinical investigations comparing the mechanical success of custom and prefabricated abutments and screws.