Keratin mediated protection of eroded enamel against abrasion - A pilot study

This in vitro study aimed to assess keratin's role in protecting eroded enamel by evaluating retention and stability of the keratin-mediated mineralised layer following toothbrushing.

Eighty polished enamel specimens with artificially induced erosive lesions (0.3% citric acid, pH2.7) were randomly assigned to five surface treatment groups: control (C), deionised water (DW), 1450 ppm sodium fluoride (NaF), keratin (K), and TEGDMA cross-linked keratin (KT). Samples were brushed with two layers of treatment material and allowed to dry for 3 min at 34 °C. Samples were remineralised in artificial saliva for 24 hrs before subjected to 45 or 240 toothbrushing strokes. Retention and stability of the mineralised layer were assessed using step height, surface microhardness, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS).

All groups showed similar step height trends, with an increase after remineralisation followed by a decrease after brushing. However, K demonstrated significantly higher step height than all other groups after both brushing conditions (p < 0.0001). Microhardness trends were comparable across groups, but after brushing, K exhibited significantly greater microhardness than C, DW, and NaF under both brushing conditions (p < 0.005). KT differed significantly from NaF only after 45 strokes (p < 0.005). SEM and EDS analyses confirmed retention of the mineralised layers in K and KT.

Keratin-mediated mineralised layers provided better protection of eroded enamel against abrasive challenges compared with other surface treatments, while maintaining retention after toothbrushing.

Keratin-mediated mineralised layer forms a protective layer which is resistant to abrasive challenges.