Evaluation of physicochemical, optical, and ultrastructural characteristics of different dental whitening toothpastes

Abstract

Objective: To compare optical, morphological, and physicochemical characteristics of whitening and conventional toothpaste. Material and Methods: The following groups were established: G1: Colgate Máxima Proteção; G2: Closeup White Now; G3: Sorriso Xtreme White 4D; G4: Colgate Luminous White; G5: Closeup Extra Whitening; G6: Oral-B Complete; G7: Oral-B 3D White; G8: Sensodyne Whitening. Scanning Electron Microscopy (SEM) with an X-Ray Energy-Dispersive Spectrometer (EDS) was used to characterize the morphology of the abrasive particles. Images were adjusted by spectral-domain Optical Coherence Tomography (OCT) from each toothpaste to characterize the different phases present in the samples. Images of different toothpastes were also compared using an optical microscope (OM). Physicochemical analysis was performed using Fourier Transform Infrared Spectroscopy (FTIR) to characterize the main components in each toothpaste analyzed. Results: The FTIR analysis showed a high content of silica and calcium carbonate as abrasive agents in toothpastes, especially silica in whitening toothpastes. OCT demonstrated the presence of reflective particles in G2, G4, and G7. SEM with EDS confirmed the high content of large silica (abrasive) particles in all whitening toothpastes except G5. Conclusion: All analyses revealed the absence of whitening agents in the composition of the whitening toothpastes and a significant amount of abrasives, such as silica and reflective particles, which are mainly responsible for the apparent whitening effect on the tooth structure.