Evaluation of time-dependent dimensional changes in dental casts fabricated from polylactic acid using fused filament fabrication additive manufacturing

To evaluate the dimensional stability over time of full-arch dental casts fabricated using Fused Filament Fabrication (FFF) with three distinct polylactic acid (PLA)-based filaments intended for dental use. A maxillary typodont was digitized using a high-precision laboratory scanner, and the resulting standard tessellation language (STL) file was created using an FFF printer with three PLA-based materials: Filadental Tray PLA (FT), Filadental Plaster White PLA (FG), and Aligner Spezial Grey PLA (FA). Ten casts were fabricated per material. Each cast was stored at room temperature and scanned at 1 day (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), and 4 weeks (T4). Dimensional deviations relative to the reference STL were assessed using root mean square (RMS) analysis in five anatomical regions. Data were analyzed with a generalized linear model at a significance level of p