Dental amalgam, or silver filling material, is a mixture of mercury, and an alloy of silver, tin and copper. The release of mercury in silver fillings is so small that it is much less than what patients are exposed to in food, air and water. There are, however, other materials that can be used for restorations. These include gold, porcelain, and composite resins. Fluoride is a compound of the element fluorine, which is found universally throughout nature in water, soil, air and in most foods. Fluoride is absorbed easily into the tooth enamel, especially in children's growing teeth. Once teeth are developed, fluoride makes the entire tooth structure more resistant to decay and promotes remineralization, which aids in repairing early decay before the damage is visible. Radiographs, or x-rays, help your dentist determine the presence or degree of periodontal disease, abscesses, and many abnormal growths such as cysts and tumors. They can help pinpoint the location of cavities and other signs of disease that may not be possible to detect through a visual examination. All health care providers are sensitive to patients' concerns about exposure to radiation. Your dentist has been trained to prescribe radiographs when they are appropriate and to tailor the radiograph schedule to your individual needs. By using state-of-the-art technology, such as digital radiography, and by staying knowledgeable about recent advances, your dentist knows which techniques, procedures and X-ray films can minimize your exposure to radiation.