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

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).

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).

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).

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.