Is Dental Amalgam a Higher Risk Factor rather than Resin-Based Restorations for Systemic Conditions? A Systematic Review

Objective: The aim of this study was to confirm the hypothesis that patients with one or more amalgam restorations have an increased risk for systemic diseases rather than patients with resin-based restorations. Data: The data search produced an initial 3568 total number of records. All titles and abstract were reviewed by five independent examiners, and only 36 records were selected for full text in depth examination. Out of these, only nine publications matched the inclusion criteria and were included in this systematic review. Sources: Electronic databases (MEDLINE, Scopus, Embase, and Web of Knowledge) were searched up to June 2019. In addition, a manual search was carried out on journals related to this topic. Study selection: All selected human clinical studies compared patients with dental amalgam restorations to patients with non-amalgam restorations on restorative material related diseases/health conditions with at least 50 patients and a reasonable follow up. The systemic effects of dental restorations were analyzed. As for any systemic effects, there was no difference between amalgam and composite restoration. Conclusions: With the limitations of the few available randomized controlled trials (RCTs) on the matter, amalgam restorations, similarly to other modern resin-based materials, were not related to an increased risk of systemic diseases or conditions. Clinical significance: On the basis of the available RCTs, amalgam restorations, if compared with resin-based fillings, do not show an increased risk for systemic diseases. There is still insufficient evidence to exclude or demonstrate any direct influence on general health. The removal of old amalgam restorations and their substitution with more modern adhesive restorations should be performed only when clinically necessary and not just for material concerns. In order to better evaluate the safety of dental amalgam compared to other more modern restorative materials, further RCTs that consider important parameters such as long and uniform follow up periods, number of restorations per patient, and sample populations representative of chronic or degenerative diseases are needed.