How safe, clinically effective, and cost-effective are composite resin and amalgam dental filling materials?
We are very pleased to present the first Canadian Armed Forces Dental Corps’ post, by Lieutenant-Colonel Dr. Dwayne Lemon, Senior Clinical Practice Leader
Last year, as part of its continuous quality improvement program, the Canadian Armed Forces Dental Corps initiated an evaluation of its restorative practice, particularly its choice of direct restorative materials for treating caries.
The Dental Corps asked the Canadian Agency for Drugs and Technologies in Health (CADTH) to critically appraise the existing literature on the suitability of amalgam- and resin-based composite as restorative materials. The resulting report Composite Resin and Amalgam Dental Filling Materials: A Review of Safety, Clinical Effectiveness and Cost-effectiveness was published in June 2012.
Three research questions were asked:
- What is the evidence for the safety of dental amalgams compared to resin composites when used as filling material on permanent teeth?
- What is the evidence regarding the clinical effectiveness of dental amalgams compared to resin composites when used as filling material on permanent teeth?
- What is the cost-effectiveness of dental amalgams compared to resin composites when used as filling materials on permanent teeth?
An initial literature search found 386 citations which, when exposed to their inclusion criteria, was reduced to 20 articles based on 6 unique trials; two Randomised Controlled Trials (RCTs) evaluating safety of amalgam, two RCTs comparing the efficacy of amalgam and composite, and two economic studies evaluating and comparing the costs associated with the use of both filling materials.
The report’s conclusions to the above questions were:
- The use of amalgam dental fillings in children did not result in different neurobehavioral, renal, or immunological outcomes compared to the use of composite. Moreover, the current review revealed that further clinical research is needed to answer questions about the potential harms caused by the exposure to bisphenol A from composite materials,
- The comparative efficacy evaluation suggested that amalgam fillings have a greater longevity than composite materials and less demand for repair, and
- The initial cost for placing dental amalgam is slightly cheaper than the cost for composite fillings; however, the cost difference tends to increase when taking into considerations the longevity differences of the two materials.
Recently, results from another study1 published by researchers at the University of Michigan questioned the historical means of measuring mercury exposure attributed to dental amalgam fillings. The study found that mercury from fish consumption could account for as much as 70% of that measured in the urine of those who consume fish in their diet. In other words, mercury exposure due to amalgam—as measured in urine mercury output—could be significantly overestimated.
In light of the present dental literature evidence, including CADTH’s systematic review, the Canadian Armed Forces Dental Corps is confident in the safety of amalgam (environmental and patient) and shall be interested to review future research on composite safety. Comparing the efficacy, longevity, and cost, amalgam appears to be the better of the two products.
1. Sherman LS, et al. New Insight into Biomarkers of Human Mercury Exposure Using Naturally Occurring Mercury Stable Isotopes, Environ Sci Technol, 2013, 47 (7), pp 3403–3409
Any opinion expressed in this article is the opinion of the author and does not constitute the official opinion or policy of the Department of National Defence or the Canadian Armed Forces.