Fit of three-unit anterior fixed dental prosthesis frameworks fabricated by different manufacturing techniques

This in vitro study aimed to evaluate different fabrication techniques for anterior cobalt-chromium (Co-Cr) three-unit fixed dental prostheses (FDPs) and their effects on the fit of maxillary central incisor and canine abutments.

Five fabrication techniques were evaluated as the experimental groups: manual wax carving and casting (Cast), milled wax and casting (CAW), 3D-printed polymers and casting (3DP), direct metal laser sintering (DMLS), and selective laser melting (SLM). Three-unit FDP frameworks were designed for the prepared maxillary central incisor and canine teeth, and Co-Cr specimens were fabricated (n = 10). Marginal (MDV), chamfer (CDV), axial (ADV), incisal (IDV), and overall discrepancy values (ODV) were evaluated using the silicone replica technique (SRT) and statistically analyzed using two-way analysis of variance (ANOVA)(α = 0.05).

Fabrication technique significantly affected measurements (p < 0.001), while tooth type did not. No differences in CDV, ADV, or IDV were found between canine and central incisor (P > 0.05). The 3DP technique showed higher MDV, CDV, and ODV than others (P < 0.05), and higher ADV than DMLS and SLM (P < 0.05). For IDV, 3DP had higher values in canine teeth compared to all techniques, and in central teeth compared to Cast, DMLS, and SLM (P < 0.05).

SLM showed a more favorable overall discrepancy than the lost-wax technique. Additionally, DMLS offers a comparable and viable alternative for fabricating anterior 3-unit FDP frameworks.