TEM of unstained human coronal dentin (D) bonded with a self-etching adhesive demonstrating 2–3 μm thick hybrid (H) and adhesive (A) layers, covered with resin composite (C). Black areas are weak solvent-rich phases, which remain after insufficient drying, disclosed with metallic silver via a nanoleakage test. (Courtesy Franklin R Tay; original magnification 10,000×.)