Tooth whitening enamel layer may also be gradually thinned or even perforated by the various forms of tooth wear. Teeth may be darkened by a buildup of surface stains (extrinsic staining), which hides the natural tooth color; or the tooth itself may discolor (intrinsic staining). Extrinsic stains can become internalised through enamel defects or cracks or as a result of dentine becoming exposed but most extrinsic stains appear to be deposited on or in the dental pellicle. Causes of extrinsic staining include: Changes in the thickness of the dental hard tissues would result in intrinsic discolouration. There are a few causal factors
Baby Tooth Survey Baby Tooth Survey The Baby Tooth Survey was initiated by the Greater St. Louis Citizens' Committee for Nuclear Information in conjunction with Saint Louis University and the Washington University School of Dental Medicine as a means of determining the effects of nuclear fallout in the human anatomy by examining the levels of radioactive material absorbed into the deciduous teeth of children. Founded by the husband and wife team of physicians Eric and Louise Reiss, along with other scientists such as Barry Commoner and Ursula Franklin, the research focused on detecting the presence of strontium-90, a cancer-causing radioactive isotope created by