Comparison of microhardness, surface roughness, retain–>Candida albicans adhesion, and color stability among TiO₂-coated and uncoated conventional, milled, and 3D printed denture base materials

J Prosthet Dent. 2026 Aug 18:S0022-3913(26)00524-X. doi: 10.1016/j.prosdent.2026.07.019. Online ahead of print.

ABSTRACT

STATEMENT OF PROBLEM: Studies investigating the effect of the titanium dioxide (TiO₂) coating on the microhardness, surface roughness, Candida albicans (C albicans) adhesion, and color change of conventionally manufactured, milled, and printed denture bases are lacking.

PURPOSE: The purpose of this in vitro study was to evaluate the microhardness, surface roughness, C albicans adhesion, and color change of different TiO₂-coated and noncoated denture bases.

MATERIAL AND METHODS: Polymethyl methacrylate (PMMA) disks were fabricated using different fabrication methods: conventionally heat polymerized, milled, and 3 dimensionally (3D) printed (N=240). Half of the specimens’ surfaces were coated with TiO₂ by atomic layer deposition (ALD). The microhardness of specimens was measured, yielding Vickers hardness numbers. Surface roughness was measured using a profilometer. C albicans adhesion was quantified as colony-forming units per milliliter (CFU/mL). Color difference between coated and noncoated specimens was evaluated using the CIEDE2000 formula. Factorial and 2-way ANOVA and the Pearson correlation analyses were used for statistical analyses (α=.05).

RESULTS: The production method and the coating status of the specimens affected the microhardness, surface roughness, and C albicans adhesion (P<.001). Surface roughness and C albicans adhesion were positively correlated (P<.001, r=0.904). The color change between TiO₂-coated and noncoated specimens was affected by the color and production method (P<.001).

CONCLUSIONS: TiO₂-coated, milled specimens demonstrated the highest microhardness, lowest surface roughness, and reduced C albicans adhesion. The original pink-colored, milled specimens showed the least color change. Milled PMMAs are processed under high pressure and temperature, resulting in lower residual monomer levels, reduced porosity, and improved material properties.

PMID:42613267 | DOI:10.1016/j.prosdent.2026.07.019