Dimensional stability of additively manufactured diagnostic maxillary casts: Influence of cast-base design, PLA filament type, infill density, and storage duration.

STATEMENT OF PROBLEM: The choice of materials and printing strategies in dental cast fabrication may influence accuracy. Evidence regarding the impact of different cast base designs, various polylactic acid (PLA) filaments, and printing processes on the dimensional stability of additively manufactured (AM) diagnostic maxillary casts is lacking.

PURPOSE: The purpose of this in vitro study was to evaluate the effects of cast-base design, PLA filament type, and infill density on the dimensional stability of AM diagnostic maxillary casts over a 4-week storage duration.

MATERIAL AND

METHODS

A reference maxillary cast was printed with 4 PLA filaments-eSun PLA+ (ES), BambuLab PLA (BL), Weiton 3D dental-grade PLA (W3D), and Filadental gypsum-reinforced PLA (FD)-fabricated with either a hollow or solid base design and 3 infill densities (5%, 20%, 35%) using a fused filament modeling (FFM) printer. Casts were scanned at 1 day and 1, 2, 3, and 4 weeks after fabrication. Scans were superimposed onto the reference cast to calculate regional and overall cast deviations. Data were analyzed with a generalized linear model and Bonferroni-corrected post hoc tests (α=.05).

RESULTS

Cast-base design, filament type, infill density, and storage duration had significant effects on dimensional stability across all regions (P<.001). BL exhibited the lowest deviations at all time points, while FD showed the highest, particularly in hollow-base and 5% infill density within the soft tissue region (P<.001). Cast-base design influenced accuracy in a region-dependent manner, with hollow bases performing better in posterior and entire arch areas, whereas solid bases showed lower deviations in soft tissue regions. The 5% infill density resulted in the highest deviations across all anatomic regions (P<.001).

CONCLUSIONS

The dimensional stability of FFM-printed casts was influenced by the material formulation, structural design, and internal support architecture. With adequate filament selection and printing settings, tested casts exhibit stable geometry for a minimum of 4 weeks.