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Health Effects From Removal of Amalgam Restorations in Patients With Symptoms Allegedly Related to Dental Amalgam

This study has been completed.
Uni Research
Information provided by (Responsible Party):
Lars Bjorkman, Uni Research Identifier:
First received: June 29, 2006
Last updated: August 27, 2012
Last verified: August 2012
The aim of the project is to study changes in symptom load after removal of all dental amalgam restorations in patients with symptoms allegedly related to amalgam.

Condition Intervention Phase
Adverse Effects
Dental Restoration, Permanent
Procedure: Removal of dental amalgam restorations
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Health Effects From Removal of Amalgam Restorations in Patients With Symptoms Allegedly Related to Dental Amalgam - A Study of Patients Examined at the Dental Biomaterials Adverse Reaction Unit in 1993 to 1999

Further study details as provided by University of Bergen:

Primary Outcome Measures:
  • Changes of subjective health complaints [ Time Frame: Five years ]
  • Changes over time of the MMPI-profile [ Time Frame: Five years ]
  • Quality of life improvement [ Time Frame: Five years ]

Secondary Outcome Measures:
  • Reduction of mercury in blood serum [ Time Frame: One year ]

Enrollment: 50
Study Start Date: September 2002
Study Completion Date: March 2010
Primary Completion Date: March 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Treatment group Procedure: Removal of dental amalgam restorations
Removal of dental amalgam restorations by patient's own dentist. Fillings will be replaced with e.g. resin based filling material, metalloceramic restorations, and ceramic materials. Rubber dam will be used during removal of amalgam restorations.
No Intervention: Reference group

Detailed Description:
Patients referred from dentists and physicians in the period 1993 to 1999 to the Dental Biomaterials Adverse Reaction Unit, Department of Health, UNIFOB AS, for symptoms related to amalgam restorations are randomized into treatment group (n=20) or reference group (n=20). All patients in the treatment group are followed 3, 12, 36 and 60 months after completion of amalgam removal with questionnaires on health outcomes, Minnesota Multiphasic Personality Inventory-2 (MMPI-2) and laboratory tests.

Ages Eligible for Study:   25 Years to 55 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Referred for examination of general health complaints related to amalgam
  • Health complaints from at least three different organ systems
  • Dental amalgam restorations present
  • Data available on concentration of mercury in blood and urine at the initial examination
  • Patient agreed to be contacted after the examination

Exclusion Criteria:

  • Serious disease (incl. severe allergy to foodstuff and severe rheumatoid arthritis)
  • Mental instability or psychiatric disease
  • Cases with complicated dental rehabilitation (incl. bridge prostheses)
  • Allergy to dental replacement materials
  • Severe periodontitis
  • High caries activity
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Please refer to this study by its identifier: NCT00346944

UNIFOB AS, Dental Biomaterials Adverse Reaction Unit
Bergen, Norway, NO-5009
Sponsors and Collaborators
University of Bergen
Uni Research
Principal Investigator: Lars Björkman, DDS, PhD University of Bergen