Can removal of amalgam restorations reduce health complaints in patients with medically unexplained physical symptoms?

Abstract

Design Three groups of non-equivalent patients using a prospective cohort study design. Patients who credited their medically unexplained symptoms (MUPS) to their dental amalgam restorations (amalgam cohort) were compared to two other groups: patients with MUPS who did not credit their symptoms to amalgam (MUPS cohort) and those who recognised themselves as healthy (healthy cohort). All participants initially filled in a questionnaire (Q1) which included the primary outcome: General Health Complaints index (GHC-index). The SF-36 Physical and Mental Component Summary was also included as a secondary outcome. Other outcomes, including blood, were collected but results will be reported in other publications. Patients in the amalgam and MUPS cohorts were assessed by their general physician (GP) to ensure their complaints met the criteria for MUPS. The amalgam cohort then had their amalgams removed by their dentist and, one year later, filled in the questionnaire again (Q2). The MUPS and healthy cohorts completed the Q2 two years after the Q1.

Cohort selection Recruitment information for the amalgam cohort was sent to all dentists and GPs in Norway, and advertised via the Directorate of Health website and the Norwegian Dental Association. Once potential participants were identified, they were required to be assessed by both a dentist and GP to declare that oral and systemic diseases were adequately treated. The risk of deterioration of dental and medical health through participation in the study was also disclosed. For the amalgam cohort, patients had to have at least one amalgam filling and attribute the presence of these restorations to unexplained health complaints which had been present for at least three months. Patients in the MUPS cohort were recruited by their GP. These patients also had to have had unexplained health complaints for at least three months; however, the key difference being they did not attribute these complaints to amalgams. The healthy cohort was primarily recruited via dentists taking part in the study and patients self-assessed as being healthy. Both the MUPS and healthy cohorts were recruited regardless of amalgam status.

Data analysis Descriptive statistics presented continuous data, and categorical data were presented as frequencies. Differences between the cohorts were analysed with analysis of variance (ANOVA) with covariate adjustment. Potential predictors of the primary outcome variable were analysed using multivariate analysis.

Results In the amalgam, MUPS and healthy cohorts, 32, 28 and 19 patients, respectively, completed participation in the study. The GHC-index significantly reduced (p <0.001) between Q1 and Q2 in the amalgam cohort but not in the other cohorts. The change in the GHC-index (change in score) was greater in the amalgam cohort compared to the MUPS cohort and this was statistically significant (p = 0.004), indicating a greater reduction in health complaints.

Conclusions General health complaints in patients with MUPS, that attributed their symptoms to their dental amalgams, reduced after removal of dental amalgam restorations.