Prospective Cohort Study of Health Complaints
Condition: Health Complaints Attributed to Dental Amalgam Restorations
Study type: Observational

Summary: 
      The aim of this study is to evaluate if amalgam removal is associated with improved
      self-reported health, compared to no amalgam removal. The main target group consists of a
      group of patients with medically unexplained physical symptoms (MUPS), which they attribute
      to dental amalgam restorations. The patients should furthermore express the wish to have
      these amalgam fillings removed. The project is designed as a prospective cohort study,
      consisting of three groups recruited separately. The main target group will be compared with
      two comparison groups: one group of patients with MUPS recruited from general practice and
      one group of healthy study patients, recruited at dental practice. The primary research
      question is if amalgam removal is associated with improved self-reported health, compared to
      no amalgam removal, one year after completed amalgam removal.
    

Detailed description: 
      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.
    

Intervention name(s): Removal of dental amalgam restorations
Intervention type(s): Device
Intervention description(s): Patients in the "amalgam cohort" will have all dental amalgam restorations removed and replaced with other restorative materials used in modern dentistry. Amalgam removal will be performed by the patient's regular dentist or another dentist chosen by the patient.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The study population will be selected from primary care clinics and dental clinics in
        Norway.
      
Biospecimen description: 
      Serum
    
Keywords: Health complaints; Amalgam; Mercury; Plasma; Cytokine