Objective: This study assessed the biofilm formation of C. albicans on milled and 3D-printed denture resin surfaces and compared it to a control group of conventional heat-polymerized polymethylmethacrylate (PMMA) resin group.

Methods: Three groups of denture resin samples (n = 27) were fabricated: milled (Ivotion, Ivoclar Vivadent), 3D-printed (Saremco Print Denturetec), and heat-polymerized PMMA controls. Samples (8 mm × 3 mm) were CAD-designed, manufactured, quality-checked, and sterilized. C. albicans (GEGE1122.01) biofilms were grown on resin discs, incubated at 37 °C for 16 h, detached, and quantified. SEM analysis assessed biofilm morphology. Statistical analysis was conducted using non-parametric tests (p < 0.05).

Results: The lowest median biofilm attachment (1.2 × 10⁶ CFU/biofilm, IQR: 3.4 × 10⁵ - 5.6 × 10⁶) with high variability was observed in the control group. The milled group displayed significantly higher biofilm formation (6.4 × 10⁶ CFU/biofilm, IQR: 5.9 × 10⁶ - 7.6 × 10⁶, p = 0.0051) with least variation. The biofilm attachment on 3D-printed discs (4.8 × 10⁶ CFU/biofilm, IQR: 3.6 × 10⁶ - 6.2 × 10⁶) was intermediate between the control and milled groups. SEM findings revealed sparse microcolonies with dense, multi-layered biofilms of yeast and pseudohyphal forms in the control and milled groups. 3D-printed group had moderately dense biofilms, where yeast and pseudohyphae were dominant, but true hyphae were also consistently observed.

Conclusion: This study reveals significant differences in the C. albicans biofilm formation across the resin types, with 3D-printed surfaces showing increased hyphal growth and potential for higher virulence.

Clinical significance: Understanding the impact of fabrication methods on microbial colonization is essential for improving denture hygiene and patient outcomes. Dentists and prosthodontists should consider these findings when selecting materials for patients at high risk of fungal infections, such as immunocompromised individuals or elderly denture wearers.