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included warning labels regarding: (1) possible harm of mercury vapors; (2) disclosure of mercury content; and (3) contraindications for persons with known mercury sensitivity. Also in this final rule, the FDA noted that there is limited information regarding dental amalgam and the long-term health outcomes in pregnant women, developing fetuses, and children under the age of six.38 With regard to clinical efficacy of dental amalgam, results comparing longevity of amalgam to other restorative materials are inconsistent. The majority of meta-analyses, evidence-based reviews, and RCTs report comparable durability of dental amalgam to other restorative materials,42-47 while others show greater longevity for amalgam.48,49 The comparability appears to be especially true when the restorations are placed in controlled environments such as university settings.42 Class I amalgam restorations in primary teeth have shown in a systematic review and two RCTs to have a success rate of 85 to 96 percent for up to seven years, with an average annual failure rate of 3.2 percent16,46,49 Efficacy of Class I amalgam restorations in permanent teeth of children has been shown in two independent randomized controlled studies to range from 89.8 to 98.8 percent for up to seven years.46,48 With regard to Class II restorations in primary molars, a 2007 systematic review concluded that amalgam should be expected to survive a minimum of 3.5 years and potentially in excess of seven years.50 For Class II restorations in permanent teeth, one meta-analysis and one evidence-based review conclude that the mean annual failure rates of amalgam and composite are equal at 2.3 percent.42,45 The meta-analysis comparing amalgam and composite Class II restorations in permanent teeth suggests that higher replacement rates of composite in general practice settings can be attributed partly to general practitioners’ confusion of marginal staining for marginal caries and their subsequent premature replacements. Otherwise, this meta-analysis concludes that the median success rate of composite and amalgam are statistically equivalent after ten years, at 92 percent and 94 percent respectively.42 The limitation of many of the clinical trials that compare dental amalgam to other restorative materials is that the study period often is short (24 to 36 months), at which time interval all materials reportedly perform similarly.51-55 Some of these studies also may be at risk for bias, due to lack of true randomization, inability of blinding of investigators, and, in some cases, financial support by the manufacturers of the dental materials being studied. Recommendation: There is strong evidence that dental amalgam is efficacious in the restoration of Class I and Class II cavity restorations in primary and permanent teeth. Composites Resin-based composite restorations were introduced in dentistry about a half century ago as an esthetic restorative material56,57, and composites increasingly are used in place of amalgam for the restoration of carious lesions.58 Composites consist of a resin matrix and chemically bonded fillers.42 They are classified according to their filler size, because filler size affects polishability/esthetics, polymerization depth, polymerization shrinkage, and physical properties. Hybrid resins combine a mixture of particle sizes for improved strength while retaining esthetics.59 The smaller filler particle size allows greater polishability and esthetics, while larger size provides strength. Flowable resins have a lower volumetric filler percentage than hybrid resins.60 Several factors contribute to the longevity of resin composites, including operator experience, restoration size, and tooth position.48 Resins are more technique sensitive than amalgams and require longer placement time. In cases where isolation or patient cooperation is in question, resin-based composite may not be the restorative material of choice.61 Bisphenol A (BPA) and its derivatives are components of resin-based dental sealants and composites. Trace amounts of BPA derivatives are released from dental resins through salivary enzymatic hydrolysis and may be detectable in saliva up to three hours after resin placement.62 Evidence is accumulating