Ultrastructural investigation of pellicle modification by statherin-derived peptide associated with epigallocatechin-3-gallate to prevent dental erosion: In situ proof-of-concept

OBJECTIVE: This ultrastructural study aimed at exploring whether rinsing with epigallocatechin-3-gallate (EGCG) combined with statherin-derived peptide (StN15pSpS) increases acquired enamel pellicle (AEP) protectivity against dental erosion. MATERIAL AND METHODS: in situ-AEP was formed by three volunteers using bovine enamel specimens fixed to individual acrylic splints. After 3 min of intraoral exposure, volunteers rinsed for 1 min with 10 mL of one of the following solutions: (1) deionized water (negative control), (2) 0.46 mg/mL EGCG, or (3) 0.46 mg/mL EGCG combined with 1.88 × 10⁻⁵ M StN15pSpS. Enamel samples were collected after 3 min and subsequently exposed to either 1 % citric acid (pH 2.5) or 0.01 M HCl (pH 2.0) for 10 s. The ultrastructure of the enamel surface was analyzed by transmission electron microscopy (TEM). RESULTS: Despite an inter-individual variability in pellicle ultrastructure, the results suggest qualitatively a protective potential of the EGCG-StN15pSpS combination against acidic attack. TEM revealed that rinsing with EGCG and StN15pSpS increased pellicle thickness and electron density, protecting enamel against citric and hydrochloric acid challenges. Compared to controls, pellicles showed reduced disintegration, minor erosion, and overall enhanced structural stability. CONCLUSIONS: The data point to a synergistic effect of polyphenol-containing EGCG with StN15pSpS and suggest this combination as promising mouth rinsing component with protective capacity against dental erosion. CLINICAL SIGNIFICANCE: Combining EGCG with the statherin-derived peptide StN15pSpS may enhance the acquired enamel pellicle's resistance to acidic erosion. This suggests potential for developing protective mouthrinses to reduce dental erosion risk.