Organic chromogens in dental enamel and dentin

Organic chromogens are the molecular entities responsible for the coloration and discoloration of dental enamel and dentin. These substances consist of complex organic molecules containing chromophores—groups of atoms with conjugated double bonds that absorb specific wavelengths of visible light (Joiner, 2006). Chromogens can be extrinsic, originating from external sources like coffee, tea, or tobacco, or intrinsic, resulting from systemic factors during tooth development or age-related changes in the dentin structure (Kwon & Wertz, 2015). In clinical dentistry, these molecules are the primary targets for bleaching agents such as hydrogen peroxide and carbamide peroxide. These agents penetrate the tooth structure and release free radicals that chemically oxidize the chromogens, breaking their double bonds and converting them into smaller, non-pigmented molecules, thereby whitening the tooth (Eimar et al., 2012). This oxidation process is the fundamental mechanism behind most professional and over-the-counter tooth whitening treatments.

Other names

Dental chromogensTooth pigmentsIntrinsic stainsExtrinsic stainsOrganic tooth stains

Oxidation of conjugated double bonds in chromophores by reactive oxygen species, leading to the breakdown of large pigmented molecules into smaller, colorless fragments (Joiner, 2006; Kwon & Wertz, 2015).