Assessing the influence of titanium dioxide nanotubes incorporation on thermal and thermomechanical characteristics of 3D-printed denture base resin.

Purpose: This study aims to evaluate the effects of adding titanium dioxide (TiO₂) nanotubes (NTs) to three-dimensional (3D) printed denture base resin on the thermal and thermomechanical properties, which have high clinical relevance.

Materials and methods: TiO₂ NTs with dimensions of 30-70 nm in diameter and 2-4 µm in length were added to the denture base resin at concentrations of 0.0 (control), 1.0, 2.0, 3.0, 4.0, and 5.0 wt.%. A total of 120 samples were printed with 60 samples for hot-disc device tests (thermal conductivity [κ], thermal diffusivity [D] and volumetric heat capacity [ρC_p] tests) and 60 samples for thermomechanical analyzer (TMA) device tests (coefficient of thermal expansion [CTE, α], thermal strain [ϵ], and elastic modulus in response to temperature changes). The collected data were analyzed with ANOVA followed by Tukey's post hoc test (α = 0.05).

Results: The results revealed that increasing the TiO₂ NT concentration improved all the thermal properties. However, in the thermomechanical tests, an improvement was observed only in the 1.0 wt.% and 2.0 wt.% TiO₂ NT composite groups, and a significant decline was observed in the remaining groups. Fourier Transform Infrared Spectroscopy (FTIR) results revealed no alteration in the chemical structure of the resin. However, the degree of conversion (DC) of the nanocomposites after polymerization was significantly affected. The samples tested via field emission scanning electron microscopy (FESEM) with energy dispersive x-ray spectroscopy (EDX) revealed an even distribution of the TiO₂ NTs in the 3D-printed samples.

Conclusions: The improvement in the thermal and thermomechanical properties of the denture material could enhance patient satisfaction by providing better perceptions of hot and cold foods, reducing marginal deterioration, and increasing durability during mastication.