ABSTRACT

Objective: A prospective cohort study on changes of health complaints after removal of amalgam restorations was carried out at the request of the Norwegian Directorate of Health. The aim was to provide and evaluate experimental treatment to patients with health complaints attributed to dental amalgam fillings.

Methods: Patients (n=32) with medically unexplained physical symptoms (MUPS), which were attributed to dental amalgam restorations had all their amalgam restorations removed and replaced with other dental restorative materials. Samples of blood were collected before and 1 year after removal of the fillings, and concentration of inorganic mercury (I-Hg), methyl mercury (MeHg), silver (Ag) and selenium (Se) in serum was determined by inductively coupled plasma–sector field mass spectrometry.The comparison groups (one with MUPS but without attribution to amalgam [n¼28] and one group of healthy individuals [n¼19]) received no treatment. The participants responded to questionnaires at baseline and at follow-up after 1 and 5 years.

Results: Concentration of I-Hg and Ag in serum decreased significantly after removal of all amalgam restorations. Concentration of MeHg and Se in serum were not changed. Intensity of health complaints was significantly reduced after amalgam removal, but there were no statistically significant correlations between exposure indicators and health complaints.

Conclusions: Removal of all amalgam restorations is followed by a decrease of concentration of I-Hgand Ag in serum. The results support the hypothesis that exposure to amalgam fillings causes an increase of the daily dose of both I-Hg and Ag. Even though intensity of health complaints decreased after removal of all amalgam restorations there was no clear evidence of a direct relationship between exposure and health complaints.

Trial registration: The project is registered at Clinicaltrials.gov (NCT01682278

KEYWORDS: Dental amalgam; mercury;serum; subjective health complaints; cohort study

Citation: Björkman, L., Musial, F., Alræk, T., Werner, E. L., & Hamre, H. J. (2023). Mercury, silver and selenium in serum before and after removal of amalgam restorations: Results from a prospective cohort study in Norway. Acta Odontologica Scandinavica, 81(4), 298–310. https://doi.org/10.1080/00016357.2022.2143422

Objective: Many patients have medically unexplained physical symptoms (MUPS); some of them attribute their health complaints to dental amalgam fillings. The aim of this study was to assess the validity and responsiveness of General Health Complaints index (GHC-index) for measuring the symptom load in MUPS patients compared to the widely used symptom outcome measure, Giessen Subjective Complaints List (GBB-24).

Methods: Three outcome measures–GHC-index, GBB-24, and Munich Amalgam Scale (MAS)–were administered at baseline and 12 months after removal of all dental amalgam restorations. The validity and responsiveness of these symptom measures were tested against external anchors: bodily distress syndrome (BDS), SF-36 vitality, and visual analogue scale (VAS). We tested both convergent and known group validities. We also examined the predictive validity and responsiveness to changes for each instrument.

Results: All the main outcome measures showed evidence of convergent and known group validities. The GHC-index, GBB-24 and MAS were all able to detect the anticipated differences in BDS and Energy. But the GBB-24 was more efficient in discriminating the BDS compared with the GHC-index (relative efficiency: RE = 0.69; 95% CI: 0.41–0.96) and MAS (RE = 0.59; 95% CI: 0.32–0.86). Each main outcome variable revealed good predictive validity for vitality (standardized coefficient:b0.71 andR20.50). Moderate to high sensitivity to change over time was demonstrated, with GHC-index performing better.

Conclusion: The GHC-index is a valid and responsive instrument for assessing symptom load in MUPS patients attributing their health complaints to amalgam fillings and undergoing amalgam removal.

KEYWORDS: Amalgam removal; GHC-index; MUPS;responsiveness; validity

Citation: Lamu, A. N., Robberstad, B., Hamre, H. J., Alræk, T., Musial, F., & Björkman, L. (2022). Validity and responsiveness of GHC-index in patients with amalgam-attributed health complaints. Acta Odontologica Scandinavica, 80(3), 226–233. https://doi.org/10.1080/00016357.2021.1989032