- The lead content of the foil backing of 4 types of intraoral film commonly used by dentists was 69% to 85%. An environmental issue exists because these foils are typically thrown out with regular refuse, even though recycling programs exist. For a new adult patient, a full-mouth radiographic series would generate 11.2 g of waste lead; for a 6-month checkup, waste lead would only be produced if radiographs were required. In an experiment that simulated the acidic conditions that might be expected in a landfill site, 3.5-4.4 mg of lead was released during 17-hour incubation in dilute acetic acid. When distilled double-deionized water replaced the acid, 1.0-2.2 mg of lead was released by the same types of foils. Human health concerns also exist when dental assistants handle lead foil while developing radiographs and fail to change their gloves or wash their hands before handling instruments and dental paraphernalia used in the mouth. Although the amount of lead introduced into the oral cavity would be relatively small, the elimination of sources of lead exposure, especially for children, is important.