Table 1.

Inclusion and exclusion criteria for all three cohorts (source: reference 24).

	Cohort
	Amalgam	MUPS	Healthy
Inclusion criteria
Age between 20 and 70 years	x	x	x
Permanent residents in Norway	x	x	x
Able to comply with the protocol	x	x	x
Health complaints attributed (by the patient) to dental amalgam restorations	x
No attribution to amalgam and no explicit wish to remove amalgam		x
≥3 months duration of the health complaints attributed (by the patient) to amalgam restorations	x
≥3 months duration of unspecific health complaints		x
Presence of at least one amalgam filling	x
Wish to have all amalgam fillings removed	x
Examination by patient’s physician and dentist according to guidelines from the Norwegian Directorate of Health	x
Diagnosed diseases adequately treated	x	x
Patient’s general practitioner/family physician and dentist assess that the general and dental health of the patient most likely not will deteriorate due to participation in the project	x
Patient’s dentist assess that there are no major risks for complications following amalgam removal (e.g., need for root canal treatments or extractions)	x
Subjective symptoms without corresponding objective findings after medical examination(s), including symptoms not explained by patient’s diagnoses	x	x
Moderate or severe functional impairment (physician-assessed)	x	x
Subjectively healthy (self-assessed)			x
No medication (intake of vitamins and minerals allowed)			x
Exclusion criteria
Pregnancy (or planned pregnancy) and lactation	x	x	x
Life threatening disease	x	x	n.a.
Patients with ongoing cancers, severe cardiopulmonary, neurological, or psychiatric diseases (assessed by the GP)	x	x	n.a.
Organic cause of all complaints (according to checklist, see text)	x	x	n.a.

n.a.: not applicable.