title: A follow-up study of patients with subjective symptoms related to dental materials.
abstract: OBJECTIVE
  The extent to which substances released from dental materials cause adverse health effects and whether removal of dental materials results in improvement of health is a matter of dispute. The aim of the study was to investigate changes in the intensity of subjective symptoms after replacement of dental materials in patients referred for adverse reactions related to dental materials, and to compare the profiles of symptoms with those found in the general population.
  
  
  METHODS
  Information was obtained from 142 patients referred to the Dental Biomaterials Adverse Reaction Unit in Bergen, Norway. At the time of examination, all patients completed a questionnaire regarding a range of subjective symptoms. A follow-up questionnaire was sent to all patients 1 to 2 years later. Similar questionnaires were sent to a reference group of 800 persons drawn from the general population.
  
  
  RESULTS
  The follow-up questionnaires were completed and returned by 84 patients, and 441 persons in the reference group. The patient group presented higher symptom indices than the reference group (P<0.001). Generally, there was some decrease in the intensity of different symptoms in patients who had replaced dental materials. The decrease was evident regarding intraoral symptoms (P=0.022) and total symptom index (P=0.041). The group of patients who had replaced materials still had significantly higher symptom indices than those of the reference group. Patients who had not replaced dental materials did not present any reduction in symptom indices.
  
  
  CONCLUSIONS
  The pattern of symptoms was similar for the groups investigated. At the group level, the intensity of local and some general subjective symptoms was reduced after replacement of the materials, but not to the level found in the general population.
authors.affiliation: Dental Biomaterials Adverse Reaction Unit, UNIFOB, University of Bergen, Bergen, Norway. gunvor.lygre@odont.uib.no
authors.forename: Gunvor Bentung
authors.initials: GB
authors.lastname: Lygre
authors.forename: Nils Roar
authors.initials: NR
authors.lastname: Gjerdet
authors.forename: Lars
authors.initials: L
authors.lastname: Björkman
mesh_terms: D016009:Chi-Square Distribution; D003723:Dental Amalgam / Q000009:adverse effects; D003764:Dental Materials / Q000009:adverse effects*; D003793:Dental Restoration, Permanent / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006967:Hypersensitivity; D008297:Male; D008875:Middle Aged; D009059:Mouth Diseases / Q000139:chemically induced*; D019233:Retreatment; D011795:Surveys and Questionnaires
chemical_list: D003764:Dental Materials; D003723:Dental Amalgam