Health Complaints Attributed to Dental Amalgam RestorationsNCT01682278
Prospective Cohort Study of Health Complaints
An observational study of Health Complaints Attributed to Dental Amalgam Restorations, run by NORCE Norwegian Research Centre AS at 1 site in Norway.
Trial 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. Read more about this study
- Who is it for?
- Ages 20 to 70 years
- Conditions the study is for
- Health Complaints Attributed to Dental Amalgam Restorations
- What is being tested?
- Removal of dental amalgam restorations
- Type of treatment
- Medical device
- How many people
- 118 participants
- Where
- 1 siteNorway
- Study dates
- Sep 2012to 30 Jun 2021
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population will be selected from primary care clinics and dental clinics in Norway.
Who may be able to join
- 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
Show all 21Show fewer
- 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
- 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)
- diagnosed diseases adequately treated
- no attribution to amalgam and no explicit wish to remove amalgam
- Dental cohort:
- subjectively healthy without diagnosed chronic disease or prescribed medication
Who cannot join
- pregnancy (or planned pregnancy) and lactation
- life threatening disease
- patients with ongoing cancers, severe cardiopulmonary, neurological, or psychiatric diseases (assessed by GP)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Amalgam Removal in Patients With Health Complaints Attributed to Amalgam Restorations: A Prospective Cohort Study
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.
Read the 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.
- Being tested
- Removal of dental amalgam restorations
- Keywords
- Health complaints, Amalgam, Mercury, Plasma, Cytokine
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
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.
| Study group | Role | What they receive |
|---|---|---|
| Amalgam cohort | Patients with medically unexplained physical symptoms attributed to dental amalgam restorations which the patient wish to have removed. Receives: 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 1 year follow-up after completed amalgam removal
Secondary outcomes (12)
GBB-24, total score
Change score at 1 and 5 year follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
SF-36 Health Survey
Change score at 1 and 5 year follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
Munich amalgam checklist
Change score at 1 and 5 year follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
Cantril Ladder Scale
Change score at 1 and 5 year follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
Integrative Medicine Outcomes Scale
Change score at 1 and 5 year follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
Diagnostic criteria for BDS
Fulfillment of diagnostic criteria for BDS at baseline and follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
Whiteley index
Change score at 1 and 5 year follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
HADS
Change score at 1 and 5 year follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
Reclassification of symptoms
Reclassification of symptoms from MUPS to symptoms from explained organic disease at follow-up
Measured: 1 and 5 year follow-up after completed amalgam removal
Concentration of mercury in plasma
Change from baseline to 1 and 5 year follow-up
Measured: 1 year follow-up after completed amalgam removal
Concentration of cytokines in plasma
Change from baseline to 1 and 5 year follow-up
Measured: 1 year follow-up after completed amalgam removal
Self-reported health complaints - General index
Change from baseline to 5 year follow-up
Measured: 5 year follow-up after completed amalgam removal
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Sep 2012 (estimated)
- Study startSep 2012
- Primary completionNov 2018
- Study completion30 Jun 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Health Complaints Attributed to Dental Amalgam RestorationsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 118 participants (actual)
Sponsor and investigators
- Lead sponsor
- NORCE Norwegian Research Centre AS
- Sponsor type
- University, hospital or other
- Collaborators
- University of Bergen, National Research Centre of Complementary and Alternative Medicine, Norway, University of Witten/Herdecke
- Responsible party
- Sponsor
- Investigators
- Lars Björkman, PhD, Principal investigator, NORCE Norwegian Research Centre AS
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01682278
- Sponsor's protocol ID
- REK2012/331
- Status last verified
- Mar 2022
- First submitted
- 5 Sep 2012
- Last updated
- 31 Mar 2022
- Results posted
- No
- Data monitoring committee
- Yes
Publications
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.
PubMed 32810306Bjorkman 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.
PubMed 36383213Lamu 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.
PubMed 33865400
Study at a glance
From the registry record, last updated by the sponsor on 31 Mar 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Amalgam Removal in Patients With Health Complaints Attributed to Amalgam Restorations: A Prospective Cohort Study
- ClinicalTrials.gov ID
- NCT01682278
- Acronym / sponsor ID
- REK2012/331
- Keywords
- Health complaints, Amalgam, Mercury, Plasma, Cytokine
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 118 participants (actual)
- Lead sponsor
- NORCE Norwegian Research Centre ASUniversity, hospital or other
- Collaborators
- University of Bergen, National Research Centre of Complementary and Alternative Medicine, Norway, University of Witten/Herdecke
- Study start
- Sep 2012 (actual)
- Primary completion
- Nov 2018 (actual)
- Study completion
- 30 Jun 2021 (actual)
- First posted
- 10 Sep 2012 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Amalgam cohort | – | Device: Removal of dental amalgam restorationsPatients with medically unexplained physical symptoms attributed to dental amalgam restorations which the patient wish to have removed. |
| 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. |
Who may qualify
- Ages
- 20 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population will be selected from primary care clinics and dental clinics in Norway.
Key inclusion criteria (21 listed)
- permanent residents in Norway
- able to comply with the protocol
- 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
Key exclusion criteria (3 listed)
- pregnancy (or planned pregnancy) and lactation
- life threatening disease
- patients with ongoing cancers, severe cardiopulmonary, neurological, or psychiatric diseases (assessed by GP)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Removal of dental amalgam restorationsPatients 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. | Device | Amalgam cohort |
Primary outcome
Self-reported health complaints - General index
Time frame: 1 year follow-up after completed amalgam removal
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.
12 secondary outcomes
GBB-24, total score
Time frame: 1 and 5 year follow-up after completed amalgam removal
SF-36 Health Survey
Time frame: 1 and 5 year follow-up after completed amalgam removal
Munich amalgam checklist
Time frame: 1 and 5 year follow-up after completed amalgam removal
Cantril Ladder Scale
Time frame: 1 and 5 year follow-up after completed amalgam removal
Integrative Medicine Outcomes Scale
Time frame: 1 and 5 year follow-up after completed amalgam removal
Diagnostic criteria for BDS
Time frame: 1 and 5 year follow-up after completed amalgam removal
Whiteley index
Time frame: 1 and 5 year follow-up after completed amalgam removal
HADS
Time frame: 1 and 5 year follow-up after completed amalgam removal
Reclassification of symptoms
Time frame: 1 and 5 year follow-up after completed amalgam removal
Concentration of mercury in plasma
Time frame: 1 year follow-up after completed amalgam removal
Concentration of cytokines in plasma
Time frame: 1 year follow-up after completed amalgam removal
Self-reported health complaints - General index
Time frame: 5 year follow-up after completed amalgam removal
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Mar 2022.
- Results publication: PubMed 32810306Bjorkman 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.
- Derived from this study: PubMed 36383213Bjorkman 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.
- Derived from this study: PubMed 33865400Lamu 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.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Lars Björkman, PhD principal investigator
NORCE Norwegian Research Centre AS
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Health Complaints Attributed to Dental Amalgam Restorations, run by NORCE Norwegian Research Centre AS at 1 site in Norway.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 21 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 31 Mar 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Self-reported health complaints - General index (time frame: 1 year follow-up after completed amalgam removal). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT01682278, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Mar 2022.