Maria Heloísa da Conceição Tavares de Lima

This study investigates the innovative use of gold nanorods (AuNRs) as optical clearing agents to enhance detailed visualization of the cementoenamel junction (CEJ) in optical coherence tomography (OCT), a non-invasive imaging modality. Eighty extracted teeth were carefully examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to classify CEJ types. Imaging was performed under four distinct contrast conditions: air (G1), glycerol (G2), AuNRs (G3), and AuNRs combined with glycerol (G4). Statistical analysis (ANOVA and Tukey’s test, p < 0.05) showed that AuNRs, especially in G4, significantly enhanced CEJ visualization by reducing scattering and improving image contrast. Specifically, for the enamel region, the AuNRs-containing groups (G3 and G4) showed the lowest attenuation coefficients (0.0011100 and 0.0010435, respectively), compared to groups 2 and 1. The same was observed in the CEJ region: the AuNRs-containing groups (G3 and G4) showed the lowest attenuation coefficients (0.0010830 and 0.0009060, respectively). Attenuation analysis indicated greater absorption in the enamel and CEJ regions with AuNRs and glycerol, while cementum remained unaffected. The preservation of cementum suggests that the combination of AuNRs and glycerol enhanced OCT imaging without compromising tissue integrity. These results highlight the potential of AuNRs to further enhance OCT-based CEJ imaging for detecting clinically significant “gaps,” thereby advancing its role as a reliable diagnostic tool in dentistry.