Is achieved by the removal of hydroxyapatite and enamel prisms using an acid, usually 37% phosphoric acid, by the acid-etch technique creating a micromechanical bond. Because dentine has a higher organic and water content than enamel, dentine bonding requires the use of a bifunctional monomer such as HEMA (hydroxyethylmethacrylate). This has a hydrophilic terminal that can bond with the dentine surface and a hydrophobic terminal that can co-polymerize with the resin of the restorative material. Bonding systems are also used to stick orthodontic brackets onto the enamel surface. See also hybrid layer; hydroxyapatite.
Franklin P., Brunton P. Restorative materials. In Clinical Textbook of Dental Hygiene and Therapy, ed. R. S. Ireland. Blackwell Munksgaard, 2006.