effect of digital workflow contaminants and steam cleaning on the reverse torque value of implant abutment screws

Objective: this study investigated the impact of digital workflow contaminants, including scanning lacquer (sl), scanning spray (ss), and 3d printing resin (pr), on the reverse torque value (rtv) of implant abutment screws.methods: in this in vitro study, 28 implant-abutment assemblies were randomly allocated into four groups (n=7), based on the type of surface contamination: scanning lacquer (sl), scanning spray (ss), 3d printing resin (pr), and an uncontaminated control group. in the experimental groups, abutment screws and internal implant surfaces were coated with the assigned material for 1 minute, while the control group remained uncontaminated. abutments were tightened to 25 ncm, and rtv values were recorded. all specimens then underwent standardized steam cleaning, were retightened to 25 ncm, and rtv measurements were repeated.results: pre-cleaning rtv differed significantly among groups (p<0.001). the sl and ss groups exhibited significantly lower rtv values than the control and pr groups (p<0.05). after steam cleaning, significant differences remained among groups (p<0.001). the control, sl, and ss groups showed comparable rtv values, which were significantly higher than that of the pr group. following cleaning, rtv increased significantly in the sl (p=0.002) and ss (p=0.03) groups, whereas it decreased significantly in the pr group (p=0.02), and showed no significant change in the control group (p=0.051).conclusions: digital workflow contaminants can affect implant screw rtv in a material-dependent manner. steam cleaning effectively reduced torque loss caused by contamination from scanning lacquer and scanning spray, but it adversely affected rtv in implants exposed to 3d-printing resin.