In Vitro Evaluation of Surface Morphology and Roughness of TiO2-coated Clear Aligners Using Scanning Electron Microscopy and Atomic Force Microscopy.

Abstract

Aim: The study aimed to characterize the surface morphology and evaluate the surface roughness of clear aligners (CAs) coated with titanium dioxide (TiO₂) nanoparticles.

Materials and methods: In this in vitro study, thermoformed PETG samples (n = 20) were equally divided into TiO₂-coated and noncoated groups. Coated samples underwent TiO₂ nanoparticle deposition via radiofrequency (RF) magnetron sputtering. All samples were analyzed using scanning electron microscopy (SEM) for surface morphology, energy dispersive X-ray analysis (EDAX) for elemental composition, and atomic force microscopy (AFM) for surface roughness. Parameters assessed included average surface roughness (Ra), root mean square roughness (Rms), and mean peak height (mh). Statistical analysis was performed using SPSS v22.0; intergroup comparisons were made using the independent t-test.

Results: Scanning electron microscopy images showed a uniform, crack-free TiO₂ coating in the coated group, while the control group lacked such features. Energy dispersive X-ray analysis confirmed the presence of titanium and oxygen in the coated samples only. Atomic force microscopy results revealed significantly lower surface roughness values in the coated group: Ra (5.17 ± 1.28 nm), Rms (6.77 ± 1.62 nm), mh (36.11 ± 9.27 nm) compared to the control: Ra (11.96 ± 5.80 nm), Rms (14.72 ± 6.30 nm), mh (51.00 ± 7.42 nm) (p < 0.05).

Conclusion: Titanium dioxide-coated aligners demonstrated reduced surface roughness and improved surface morphology over non-coated aligners.

Clinical significance: Titanium dioxide nanoparticle coating may enhance the clinical performance of CAs by improving surface quality and reducing potential bacterial adhesion. How to cite this article: Padmanabhan SV, Kalathur Sridev A, Sankaranarayanan V, et al. In Vitro Evaluation of Surface Morphology and Roughness of TiO₂-coated Clear Aligners Using Scanning Electron Microscopy and Atomic Force Microscopy. J Contemp Dent Pract 2026;27(2):124-129.