Are Composite Fillings Safe?

White composite fillings have become very popular in the past 25 years, replacing silver amalgam metallic fillings as the material of choice. Composites certainly are unrivaled in appearance and, when placed by a competent dentist, are nearly as wear-resistant, strong, and cost-competitive as silver amalgam fillings. A concern with amalgam is that metallic mercury used to compound the silver, tin, and copper can leach out of the amalgam and may toxically accumulate in the body. There is also the concern in many communities that heavy metals from old fillings may poison the environment when they are removed. Nevertheless, we also can have concerns about the safety of all dental materials, including those used in dental composites. Composite fillings are a type of plastic, specifically poly methyl-methacrylate, which is found in the organic phase of white fillings. It has been shown that denture bases, also made from methyl methacrylate, can cause contact dermatitis in some patients from the release of uncured resin monomers. This is the ‘release phenomenon’ that some investigators [Gupta, Saxena, Pant and Pant; Toxicology International, 19(3), 2012J cite in biocompatibility studies for dental composite resins. In their conclusions, though, the authors also state that improvements in newer materials and having clinicians follow the manufacturer’s instructions while considering the technical limitations and strengths of material use can mitigate many of the potential problems arising from composite fillings; it is incumbent on the clinician to ensure that polymerization of composites is complete, reducing the unreacted toxic monomer components by using materials within the expiration guidelines, layer-curing composites, using high-intensity, frequency-compatible light curing units, and always using composites containing no Bis Phenol A (BPA) in any form.

Sincerely yours in dentistry,

Bruce R Clark, DDS, MAGD