Antifungal activities, surface roughness, and color change of 3D printed resins containing halloysite nanotubes

Background: Removable dentures are one of the common treatment modalities used to restore missing teeth. Denture stomatitis, caused by the adhesion of Candida albicans, is considered a major complication of these prostheses. The purpose of this article is to evaluate the impact of adding Halloysite Nanotubes (HNTs) on the surface roughness (Ra, µm), color change (∆E*), and Candida albicans adhesion in 3D-printed denture base resins (PDBRs). Methods: Three concentrations (0.3%,0,6%, and 0.9%wt.) of HNTs were added to two PDBRs, ASIGA and NextDent, while the control group remained without HNTs addition. The specimens were printed in a disk shape (15 × 2 mm). After printing, specimens were thermocycled (5000 cycles). Surface roughness was measured using a non-contact profilometer. Color change (∆E*) was measured using the Commission International de l’Eclairage (CIE) system coordinates (L*, a*, b*) method. C. albicans adhesion was evaluated using a colony-forming unit (CFU/mL). The collected data were statistically analyzed using ANOVA and a post-hoc Tukey test (α = 0.05). Results: The addition of HNTs showed no significant difference in surface roughness between all tested groups (P ˃0.05). Adding HNTs resulted in a slight color change at 0.3% and 0.6%, while 0.9% significantly increased the color change (P < 0.001) with a noticeable difference. Adding HNTs significantly decreased the C. albicans adhesion to PDBRs compared to pure resins (P < 0.001). Regarding the concentration effect, the effect was concentration-dependent, with 0.9% showing the lowest Candida colony count for ASIGA resin (1018.9 ± 80.0) and NextDent resins (911.1 ± 89.3). Conclusion: Adding HNTs to PDBRs did not change the surface roughness and significantly decreased C. albicans adhesion. The color was changed with HNTs to noticeable with 0.9%HNTs. Due to the antifungal activities of PDBRs containing HNTs, these PDBRs could be recommended as a method for preventing denture stomatitis.