title: Investigation of contact allergy to dental metals in 206 patients.
abstract: BACKGROUND
  Contact allergy to dental materials is poorly understood; clinical manifestations are heterogeneous.
  
  
  OBJECTIVE
  To analyse positive patch test reactions to metals (as their alloys or salts) used in dentistry together with clinical symptoms and possible relevance to dental fillings.
  
  
  METHODS
  We retrospectively analysed 206 patients who underwent patch testing with metals used in dentistry because of suspected contact allergy to them.
  
  
  RESULTS
  Twenty-eight of 206 patients had positive patch test reactions to metals used in dentistry. The number of positive patch test reactions was highest for gold sodium thiosulfate, palladium chloride, and nickel sulfate (n = 10, respectively), followed by amalgam, ammoniated mercury, and cobalt chloride (n = 4, respectively) and amalgam-mixed metals (including copper, tin, zinc, and silicon), and ammonium tetrachloroplatinate (n = 1). Only 14 (7%) of 206 patients had a clinically relevant contact allergy with conditions of the oral mucosa (n = 7 with lichen planus and n = 7 with stomatitis) and positive patch test reactions to dental metals containing the suspected allergen. Improvement of symptoms was assessed in one patient with amalgam contact allergy 2 weeks after removal of dental fillings.
  
  
  CONCLUSIONS
  Clinically relevant contact allergies to dental metals are infrequent. Gold sodium thiosulfate and palladium chloride presented the most frequent contact allergens.
authors.affiliation: Department of Dermatology and Allergology, Hannover Medical School, Hannover, Germany. raap.ulrike@mh-hannover.de
authors.forename: Ulrike
authors.initials: U
authors.lastname: Raap
authors.forename: Meike
authors.initials: M
authors.lastname: Stiesch
authors.forename: Heidi
authors.initials: H
authors.lastname: Reh
authors.forename: Alexander
authors.initials: A
authors.lastname: Kapp
authors.forename: Thomas
authors.initials: T
authors.lastname: Werfel
mesh_terms: D000328:Adult; D003722:Dental Alloys / Q000009:adverse effects*; D003793:Dental Restoration, Permanent; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006052:Gold Sodium Thiomalate / Q000009:adverse effects; D006801:Humans; D008297:Male; D019216:Metals, Heavy / Q000009:adverse effects; D009059:Mouth Diseases / Q000209:etiology*; D010328:Patch Tests; D012189:Retrospective Studies
chemical_list: D003722:Dental Alloys; D019216:Metals, Heavy; D006052:Gold Sodium Thiomalate