title: Greening of the tooth-amalgam interface during extended 10% carbamide peroxide bleaching of tetracycline-stained teeth: a case report.
abstract: At-home bleaching with 10% carbamide peroxide in a custom-fitted tray has been shown to have some minor effects on certain brands of amalgam, pertaining to mercury release, but generally, effects on amalgam are not considered clinically significant. However, in this case report, a greening of the tooth structure in certain areas immediately adjacent to amalgam restorations in the maxillary and mandibular first molars occurred during tooth whitening. Other amalgam restorations in mandibular and maxillary second molars in the same mouth did not demonstrate any green discoloration of the teeth. Upon removal of the affected amalgam restorations, recurrent decay was present in the areas of tooth greening but not in other areas adjacent to the restoration. The teeth were restored with posterior composite restorations. Whether the green discoloration was a result of some loss of material from a particular brand of amalgam, indicating leakage, or indicative of original or recurrent tooth decay is unclear in this single-patient situation. Other patients in the same study did not demonstrate this occurrence. Dentists should be ready to replace amalgam restorations should this green discoloration in adjacent tooth structure occur during bleaching, in case decay is present.
  
  
  CONCLUSIONS
  The unusual discoloration cited suggests that amalgam restorations in potentially esthetic areas, including the lingual of anterior teeth, should be replaced prior to bleaching, to avoid the problem of difficult stain removal or translucency allowing restoration visibility following bleaching.
authors.affiliation: Department of Oral Rehabilitation, School of Dentistry, Medical College of Georgia, Augusta, Georgia, USA. vhaywood@mail.mcg.edu
authors.forename: Van B
authors.initials: VB
authors.lastname: Haywood
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D000077463:Carbamide Peroxide; D003188:Composite Resins; D003723:Dental Amalgam / Q000737:chemistry*; D003731:Dental Caries / Q000175:diagnosis; D003793:Dental Restoration, Permanent; D003804:Dentin / Q000473:pathology; D004338:Drug Combinations; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008963:Molar; D016877:Oxidants / Q000009:adverse effects / Q000627:therapeutic use*; D010545:Peroxides / Q000009:adverse effects / Q000627:therapeutic use*; D012008:Recurrence; D019279:Resin Cements; D013754:Tetracyclines; D014073:Tooth Bleaching / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D014075:Tooth Discoloration / Q000139:chemically induced / Q000209:etiology*; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D003188:Composite Resins; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D019279:Resin Cements; D013754:Tetracyclines; C065770:Herculite XR; D000077463:Carbamide Peroxide; D003723:Dental Amalgam; D014508:Urea