Acid etching of dentin achieves all of the following EXCEPT:

Correct answer: D. A decrease in wettability by the adhesive

• A. Etching raises the surface free energy of the substrate.
• B. Removing the smear layer and smear plugs is a primary purpose of dentin conditioning.
• C. Etching demineralises the intertubular and peritubular dentin, exposing the collagen mesh that the adhesive infiltrates to form the hybrid layer.
• D. Correct — this is the EXCEPTION. Etching INCREASES wettability, not decreases it. Higher surface energy means a lower contact angle and better spreading of the adhesive across the substrate. Remember the chain: remove smear layer, demineralise, raise surface energy, increase wettability, improve adhesive penetration and hybrid layer formation.