Evaluation of two printing techniques for maxillary removable partial denture frameworks.

STATEMENT OF PROBLEM: Three-dimensional (3D) printing technology has gained popularity in producing removable partial denture (RPD) frameworks, including direct 3D printing of the metal framework and framework printing using castable resin, subsequently cast and processed. However, whether the technology is sufficiently accurate and precise to supersede traditional methods is unclear.

PURPOSE: The purpose of this in vitro study was to determine the accuracy and precision of 2 different methods in the fabrication of RPD frameworks, including 3D printing by selective laser melting (SLM) and digital light processing (DLP).

MATERIAL AND METHODS: Maxillary casts were digitized to design RPD frameworks. Thereby, 8 frameworks were produced for each group. The SLM group underwent a thermal finishing process after printing. In the DLP group, castable resin was printed but not cast. All frameworks were scanned to generate digital files, which were then compared with the original design using a metrology software program and manual measurements. Statistical analysis was executed using the t-test for independent specimens (α=.05) and by comparing heatmaps of the overlaid meshes.

RESULTS: The analysis of the frameworks indicated minor deviations across all specimens. Regarding accuracy, there were no significant differences between the groups (P=.986). The SLM frameworks demonstrated greater precision, with absolute deviation values of 0.13 mm compared with 0.17 mm in the DLP group (P<.001).

CONCLUSIONS: The findings underscored a high consistency between the 2 printing techniques, demonstrating a sufficiently advanced production process to yield predictable results. While the accuracy of both techniques was at a comparably high level and did not differ significantly, the SLM technique delivered RPDs with higher precision.