Fig. 4: Crystallographic integration of the mineralised layer to the underlying enamel tissue.

a STEM and (b) TEM images showing integration between native and newly grown nanocrystals of a remineralised diazone prism. Insets in (a) show SAED patterns from native and remineralised regions confirming newly grown nanocrystals co-oriented along the c-axis with respect to native nanocrystals. c HRTEM image of the interface from (b) showing no distinct boundary between native and new nanocrystals, demonstrating crystallographic integration via epitaxial remineralisation. Micrographs in (a–c) are representative images from n = 2 independent experiments. d High magnification SEM images showing new nanocrystals nucleating and extending from underlying native nanocrystals along the c-axis (representative images from n = 4 independent experiments). e TEM image, (f) EDX map, and (g) EDX spectrum confirming and distinctly showing the growth of remineralised layer on parazone prism. h TEM image showing integration and co-alignment between native and newly grown nanocrystals along the c-axis in a remineralised parazone prism. i HRTEM image of the interface from (h) showing no distinct boundary between native and new nanocrystals, confirming crystallographic integration. Insets show FFT patterns from different regions, demonstrating co-orientation. j TEM image showing a bundle of newly grown nanocrystals (marked by a white dotted boundary) nucleating on the a-axis of the native nanocrystals while growing and extending along the c-axis. Insets in (j) show SAED patterns recorded from remineralised (white box) and native (green box) regions, confirming the co-orientation between native and newly grown nanocrystals. Micrographs in (e–j) are representative images from n = 2 independent experiments.