Prospective Cohort Study of Health Complaints

• Self-reported health complaints - General index [ Time Frame: 1 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  Primary outcome is the general index from "Self-reported health complaints" (used by Sjursen et al 2011) at 1 year follow-up after completed amalgam removal. Changes from baseline to 1 year follow-up after amalgam removal of the amalgam cohort will be compared with changes in the MUPS-cohort from baseline to 2 year follow-up.
  
  

• GBB-24, total score [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• SF-36 Health Survey [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Munich amalgam checklist [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Cantril Ladder Scale [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Integrative Medicine Outcomes Scale [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Diagnostic criteria for BDS [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  Fulfillment of diagnostic criteria for BDS at baseline and follow-up
  
  
• Whiteley index [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• HADS [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Reclassification of symptoms [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  Reclassification of symptoms from MUPS to symptoms from explained organic disease at follow-up
  
  
• Concentration of mercury in plasma [ Time Frame: 1 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Concentration of cytokines in plasma [ Time Frame: 1 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Self-reported health complaints - General index [ Time Frame: 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  

• Health resource use [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Sick leave [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  
• Costs [ Time Frame: 1 and 5 year follow-up after completed amalgam removal ] [ Designated as safety issue: No ]
  

In Norway 5%-8% of the adult population believe that their amalgam fillings have affected their health adversely; and a similar proportion of the adult population has had their amalgam fillings removed for health reasons only. The Norwegian Ministry of Health and Care Services has decided to fund a project comprising experimental treatment (i.e. removal of amalgam fillings) for patients with health complaints which they attribute to dental amalgam. The aim of this study is to evaluate the intervention by measuring health complaints and quality of life before and after amalgam removal and to compare changes over time with relevant patient groups. Amalgam-attributed health complaints are heterogeneous and a variety of symptoms have been attributed to amalgam. Therefore, amalgam related health complaints are difficult to quantify. However, amalgam-attributed health complaints are largely similar to complaints experienced by patients with so called "medically unexplained physical symptoms" (MUPS). Therefore, in order to operationalize and measure the patient's subjective health complaints, the MUPS criteria and questionnaire will be applied to patients who attribute their health problems to amalgam. Furthermore, this strategy allows for the inclusion of patients suffering from MUPS, however without any attribution to amalgam. This group of patients can serve as a comparison group with a similar symptom load, but no subjective attribution to amalgam. For the interpretation of the study outcome, the natural course of the health complaints in this group is of high importance.

Therefore, the project is designed as a prospective cohort study, consisting of three groups recruited separately. The two comparison groups consist of one group of patients with MUPS recruited from general practice and one group of healthy study patients, recruited at dental practice. These study participants are recruited regardless of amalgam status. The main target group consists of a group of patients with medically unexplained physical symptoms, which they attribute to dental amalgam restorations. The patients should furthermore express the wish to have these amalgam fillings removed ("amalgam cohort"). Patients with amalgam attributed health complaints who suffer from medically explained disease but attribute their diagnosis and course of the disease to amalgam (thus, not included in the amalgam cohort), will be included in a separate case series ("amalgam - case series", to be registered as a separate study).

Patients in the "amalgam cohort" will have all amalgam fillings removed according to pre-defined criteria. Amalgam removal will be performed by the patient's regular dentist or another dentist chosen by the patient. After completed removal, patients in the amalgam groups will be examined at a Regional Dental Center of Competence. The costs of amalgam removal will be reimbursed according to pre-defined rules.