Seating accuracy of removable partial denture frameworks fabricated by different digital workflows in comparison to conventional workflow

PURPOSE: To evaluate the seating accuracy of removable partial denture (RPD) frameworks fabricated by two digital workflows involving selective laser melting (SLM) in comparison to the conventional workflow. MATERIALS AND METHODS: A Kennedy class III modification 1 partially edentulous mandibular arch was used as a master model. Three RPD framework groups were included: (1) a conventional workflow group with conventional impression and casting (CC), (2) a partial digital workflow group with conventional impression and digital fabrication (CD), and (3) a complete digital workflow group with digital impression and digital fabrication (DD). A total of 10 frameworks were produced for each group. The marginal gaps at the occlusal rests, retention arms, and reciprocating arms were measured by a traveling microscope. The data were analyzed with the one-way analysis of variance test. RESULTS: At the framework level, the most superior fit was observed for the CD group (79.5 µm) followed by DD (85.3 µm) and CC (114.2 µm) groups. The CD and DD groups were significantly superior to CC (p < 0.001). This fit pattern was consistent for the retention and reciprocating arms, while the occlusal rest fit was similar among all the groups. CONCLUSIONS: The SLM frameworks had a promising seating accuracy in comparison to conventional frameworks. The type of impression, conventional or digital, did not affect the accuracy of SLM frameworks. The differences observed in the present study are likely to be of minimal clinical significance.