Evaluation of a dental amalgam alloy containing the fluoride additive stannous hexafluorozirconate

Abstract

This study was designed to evaluate a dental alloy containing stannous hexafluorozirconate at 0.5 percent by weight, to determine how the fluoride additive might affect the physical properties of the alloy and the clinical performance of the amalgam restorations. Using established methodology, the fluoride containing alloy was evaluated in the laboratory for fluoride release, enamel uptake and solubility, strength, hardness, flow, dimensional change, corrosion resistance, and marginal leakage. Clinically, 98 pairs of test and control restorations were placed and evaluated for marginal adaptation, surface characteristics, and recurrent caries. The results indicate that the fluoride containing alloy meets the ADA specifications for amalgam alloys, though the strength properties of the amalgam are reduced. The increased susceptibility to corrosion noted in the laboratory for the fluoride-containing amalgam did not correlate with the clinical performance of the restorations, which showed no deleterious affects resulting from the addition of the fluoride compound. The reduced enamel solubility observed in the laboratory can be considered an adjunct in the prevention of recurrent caries, though no recurrent caries was reported for either the test or control restorations. Again, the prevention of recurrent caries must begin with appropriate cavity design, care in manipulation of materials and responsible diet and hygiene practices.