Effect of printing angulation on the fit of additively manufactured provisional three-unit fixed dental prostheses

Printing orientation may influence the fit of additively manufactured provisional fixed dental prostheses (FDPs). This in vitro study evaluated 108 three-unit FDPs fabricated with a liquid crystal display-based masked stereolithography printer at nine combinations of buccolingual (150°, 180°, 210°) and mesiodistal (0°, 15°, 45°) angulations, with 12 FDPs per combination. Marginal, cervical, axial, axio-occlusal, and occlusal gaps were assessed by silicone replicas seated on a cobalt–chromium master model under finger pressure. Regional means from 28 measurements per abutment underwent separate unequal-variance factorial analyses with Holm adjustment. Buccolingual effects were detected for all regions; mesiodistal effects were detected for all regions except the premolar axial gap. At 0° mesiodistal angulation, the marginal-gap difference between 150° and 180° buccolingual orientations was 624.38 μm (95% confidence interval 470.87–777.88) for premolars and 442.02 μm (323.73–560.31) for molars. The 180°/0° and 180°/15° combinations generally had lower marginal and occlusal means, but the smallest axial means occurred at 210°/0°. These findings describe the tested orientation and support configurations; they do not establish a universal optimum or clinical performance.