STATEMENT OF PROBLEM: Bonded screw-retained implant-supported prostheses may become contaminated during fabrication, leading to biological complications. Studies supporting effective cleaning methods are sparse. PURPOSE: The purpose of this in -vitro study was to compare the effectiveness of 3 different cleaning techniques for the removal of contaminants on the surfaces of bonded screw-retained implant-supported prostheses. MATERIAL AND METHODS: Forty-five screw-retained implant-supported prostheses were divided into 3 groups after their processing in the digital laboratory. Group VS included specimens cleaned using vapor steam, group ME using a multi-enzyme cleaner in an ultrasonic bath, and group 3UC using the 3-step ultrasonic cleaning method with different solutions. The presence of contaminants was determined using scanning electron microscopy (SEM) under ×200 and ×500 magnifications and energy dispersive X-ray spectroscopy (EDS). The ImageJ software program was used to locate and quantify the debris. Statistical tests, including the Wilcoxon signed-rank test, Kruskal-Wallis test, and Dunn test were used to evaluate the effectiveness of the 3 cleaning techniques. RESULTS: Statistically significant differences in the number of surface contaminants were observed at the implant-abutment interface in all 3 groups (P<
.05) after each cleaning technique, with the highest mean difference for the 3-step ultrasonic cleaning. Elements such as carbon, oxygen, titanium, and calcium showed statistically significant differences (P<
.05) compared with other elements among the groups. CONCLUSIONS: All 3 cleaning techniques reduced the contaminants on the surfaces of the screw-retained implant-supported prostheses. The 3-step ultrasonic cleaning method yielded the best results.