The authors placed 60 Class I and Class V restorations in the primary molars of children aged 4 to 10 years using a gallium alloy. Within one year after placement, the surfaces of all the restorations had deteriorated significantly due to corrosion, and the authors found remarkable amounts of corrosion products on restorations retrieved after tooth extraction or loss. The marginal integrity of many of the Class I restorations deteriorated slightly during the study; the Class V restorations showed no marginal breakdown. No other problems were detected after one year. These data indicate that the gallium alloy tested had insufficient resistance to corrosion to serve as a permanent restorative material. However, the authors suggest consideration of this alloy for use in primary teeth to reduce the exposure of children and dental professionals to mercury-containing amalgam.