Patient Satisfaction and Accuracy of Partial Denture Frameworks Fabricated using Conventional and Digital Techniques.

This case report compares a conventional and a digital workflow for manufacturing metal frameworks for maxillary and mandibular removable partial dentures (RPDs). Two sets of maxillary and mandible RPDs were produced. The metal framework of one set of RPDs was produced conventionally using the lost wax casting technique. Intraoralscanning and computer-aided designing (CAD) were used to fabricate the metal frameworks of the other set of RPDs using direct metal laser sintering (DMLS) technology. The accuracy of fit of the two sets of RPDs was evaluated after 3 months using replica models. Patient satisfaction was assessed. Two years later, the fit accuracy of the DMLS prosthesis and patient satisfaction were re-evaluated. The accuracy of fit in the maxillary RPD with the DLMS manufactured metal framework showed better results in all areas except areas of rests (457 vs. 421 µm) and the major connector (850 vs. 512 µm). The mandibular RPD with DLMS manufactured metal framework showed only in the areas of the reciprocal arm and major connector better fit accuracy compared to the conventional RPD. The patient satisfaction with the DLMS manufactured RPDs was rated equally to the conventional one. The use of digital technologies in manufacturing RPDs seems promising regarding accuracy and patient satisfaction.

Accuracy of Removable Partial Denture Frameworks Fabricated Using Conventional and Digital Technologies.

This study analyzed the fit accuracy of the removable partial denture (RPD) metal frameworks produced using digital and conventional manufacturing technologies. Mandibular RPD metal frameworks (N=15, n=3 per group) were fabricated on a representative clinical case. RPDs were fabricated using one of the following manufacturing procedures: a) conventional lost-wax casting technique (C-LW), b) conventional casting of milled sacrificial patterns (C-M), c) conventional casting of printed sacrificial patterns (C-P), d) selective laser melting (SLM), e) direct metal laser sintering (DMLS) technologies. The fit accuracy of RPD frameworks was analyzed by fabricating replicas with silicone registration material and measuring with a digital microscope. A total of 11 sites and 29 areas in the RPD metal frameworks were considered for the accuracy measurements (µm). Data were statistically analyzed using Wilcoxon signed rank and Friedman test (α=0.05). Before finishing and polishing, C-M method presented overall significantly better (P⟨.001) fit accuracy (118 µm) than those of other methods (195-265 µm). After finishing and polishing, C-M method showed overall significantly better (P⟨.033) fit accuracy (205.7 µm) than C-LW and SLM methods (285.7 µm; 249 µm) and comparable fit accuracy to that of C-P and DMLS methods. Accuracy at the minor and major connector areas of RPDs were affected from the manufacturing technologies. Clinical Implications: When accuracy of RPDs are considered, digital technologies tested presented similar results to those of conventional manufacturing method except for minor and major connector areas which necessitates further improvement.