NCT01682278

Brief 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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
118

participants targeted

Target at P50-P75 for all trials

Timeline
Completed

Started Sep 2012

Longer than P75 for all trials

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

September 1, 2012

Completed
4 days until next milestone

First Submitted

Initial submission to the registry

September 5, 2012

Completed
5 days until next milestone

First Posted

Study publicly available on registry

September 10, 2012

Completed
6.1 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

November 1, 2018

Completed
2.7 years until next milestone

Study Completion

Last participant's last visit for all outcomes

June 30, 2021

Completed
Last Updated

March 31, 2022

Status Verified

March 1, 2022

Enrollment Period

6.2 years

First QC Date

September 5, 2012

Last Update Submit

March 16, 2022

Conditions

Health Complaints Attributed to Dental Amalgam Restorations

Keywords

Health complaintsAmalgamMercuryPlasmaCytokine

Outcome Measures

Primary Outcomes (1)

  • Self-reported health complaints - General index

    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.

    1 year follow-up after completed amalgam removal

Secondary Outcomes (12)

  • GBB-24, total score

    1 and 5 year follow-up after completed amalgam removal

  • SF-36 Health Survey

    1 and 5 year follow-up after completed amalgam removal

  • Munich amalgam checklist

    1 and 5 year follow-up after completed amalgam removal

  • Cantril Ladder Scale

    1 and 5 year follow-up after completed amalgam removal

  • Integrative Medicine Outcomes Scale

    1 and 5 year follow-up after completed amalgam removal

  • +7 more secondary outcomes

Other Outcomes (3)

  • Health resource use

    1 and 5 year follow-up after completed amalgam removal

  • Sick leave

    1 and 5 year follow-up after completed amalgam removal

  • Costs

    1 and 5 year follow-up after completed amalgam removal

Study Arms (3)

Amalgam cohort

Patients with medically unexplained physical symptoms attributed to dental amalgam restorations which the patient wish to have removed.

Device: Removal of dental amalgam restorations

MUPS-cohort

Patients with medically unexplained physical symptoms without attribution to amalgam and no explicit wish to remove amalgam.

Dental cohort

Healthy comparison group: Subjectively healthy without diagnosed chronic disease or prescribed medication.

Interventions

Removal of dental amalgam restorationsDEVICE

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.

Amalgam cohort

Eligibility Criteria

Age20 Years - 70 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)
Sampling MethodNon-Probability Sample
Study Population

The study population will be selected from primary care clinics and dental clinics in Norway.

You may qualify if:

  • permanent residents in Norway
  • able to comply with the protocol
  • Amalgam Cohort:
  • Health complaints attributed (by the patient) to dental amalgam restorations
  • duration of the health complaints attributed to amalgam restorations (by the patient) at least 3 months
  • presence of at least one amalgam filling
  • the patient has expressed a wish to have all amalgam fillings removed
  • patient examined by patient's physician and dentist according to guidelines from the Norwegian Directorate of Health
  • diagnosed diseases adequately treated
  • patient's general practitioner/family physician and dentist assess that the patient's general health and dental health most likely will not deteriorate due to participation in the project
  • patient's dentist assess that there are no major risks for dental complications following amalgam removal (e.g. need for root canal treatments or extractions)
  • subjective symptoms without corresponding objective findings after medical examination(s), including symptoms not explained by patient's diagnoses,
  • moderate or severe functional impairment (assessed by the physician)
  • MUPS-cohort:
  • duration of unspecific health complaints at least 3 months
  • +6 more criteria

You may not qualify if:

  • pregnancy (or planned pregnancy) and lactation
  • life threatening disease
  • patients with ongoing cancers, severe cardiopulmonary, neurological, or psychiatric diseases (assessed by GP)

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Uni Health

Bergen, Norway

Location

Related Publications (3)

  • Bjorkman L, Musial F, Alraek T, Werner EL, Weidenhammer W, Hamre HJ. Removal of dental amalgam restorations in patients with health complaints attributed to amalgam: A prospective cohort study. J Oral Rehabil. 2020 Nov;47(11):1422-1434. doi: 10.1111/joor.13080. Epub 2020 Aug 30.

    PMID: 32810306RESULT

  • Bjorkman L, Musial F, Alraek T, Werner EL, Hamre HJ. Mercury, silver and selenium in serum before and after removal of amalgam restorations: results from a prospective cohort study in Norway. Acta Odontol Scand. 2023 May;81(4):298-310. doi: 10.1080/00016357.2022.2143422. Epub 2022 Nov 16.

    PMID: 36383213DERIVED

  • Lamu AN, Bjorkman L, Hamre HJ, Alraek T, Musial F, Robberstad B. Validity and responsiveness of EQ-5D-5L and SF-6D in patients with health complaints attributed to their amalgam fillings: a prospective cohort study of patients undergoing amalgam removal. Health Qual Life Outcomes. 2021 Apr 17;19(1):125. doi: 10.1186/s12955-021-01762-4.

    PMID: 33865400DERIVED

Biospecimen

Retention: SAMPLES WITHOUT DNA

Serum

Study Officials

  • Lars Björkman, PhD

    NORCE Norwegian Research Centre AS

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
observational
Observational Model
COHORT
Time Perspective
PROSPECTIVE
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

September 5, 2012

First Posted

September 10, 2012

Study Start

September 1, 2012

Primary Completion

November 1, 2018

Study Completion

June 30, 2021

Last Updated

March 31, 2022

Record last verified: 2022-03

Locations

NO(1)