Passive fit of milled and additively manufactured complete arch implant-supported titanium frameworks: a micro-CT analysis

BACKGROUND: To evaluate the passive fit of milled and additively manufactured titanium complete arch implant-supported frameworks (CAISFs) by using microcomputed tomography (µCT). METHODS: A maxillary model resembling all-on-4 concept was used, multiunit abutments and scan bodies were attached, and the model was digitized. Ten frameworks were produced from CAD files and allocated to 2 groups (n=5) according to the manufacturing method: milled titanium (M) and additively manufactured titanium (AM). The passive fit of CAISFs was evaluated by using the modified 1-screw test. All screws were attached and then removed, except for the terminal abutment tightened to 15 Ncm. The Primary outcome to access passive fit involved measuring marginal discrepancies for the 3 unscrewed implants at 4 points using µCT. Mann-Whitney U test assessed manufacturing methods. Kruskal-Wallis test assessed effect of implant locations and different measuring surfaces on marginal discrepancy. Aligned rank transform (ART) ANOVA was used to evaluate the effect of the interactions among all factors (α=.05). RESULTS: Regarding the passive fit, significant difference in marginal discrepancy value was found between the 2 manufacturing methods (P