Veronese I, Guzzi G, Giussani A, Cantone M C, Ripamonti D
Dipartimento di Fisica, Università degli Studi di Milano, Milano, Italy.
J Environ Radioact. 2006;91(1-2):15-26. doi: 10.1016/j.jenvrad.2006.08.002. Epub 2006 Sep 25.
Different types of materials used for dental prosthetics restoration, including feldspathic ceramics, glass ceramics, zirconia-based ceramics, alumina-based ceramics, and resin-based materials, were investigated with regard to content of natural radionuclides by means of thermoluminescence beta dosimetry and gamma spectrometry. The gross beta dose rate from feldspathic and glass ceramics was about ten times higher than the background measurement, whereas resin-based materials generated negligible beta dose rate, similarly to natural tooth samples. The specific activity of uranium and thorium was significantly below the levels found in the period when addition of uranium to dental porcelain materials was still permitted. The high-beta dose levels observed in feldspathic porcelains and glass ceramics are thus mainly ascribable to (40)K, naturally present in these specimens. Although the measured values are below the recommended limits, results indicate that patients with prostheses are subject to higher dose levels than other members of the population. Alumina- and zirconia-based ceramics might be a promising alternative, as they have generally lower beta dose rates than the conventional porcelain materials. However, the dosimetry results, which imply the presence of inhomogeneously distributed clusters of radionuclides in the sample matrix, and the still unsuitable structural properties call for further optimization of these materials.
采用热释光β剂量测定法和γ能谱法，对用于牙齿修复的不同类型材料（包括长石质陶瓷、玻璃陶瓷、氧化锆基陶瓷、氧化铝基陶瓷和树脂基材料）的天然放射性核素含量进行了研究。长石质陶瓷和玻璃陶瓷的总β剂量率比本底测量值高约10倍，而树脂基材料产生的β剂量率可忽略不计，与天然牙齿样本类似。铀和钍的比活度显著低于仍允许在牙科陶瓷材料中添加铀的时期所发现的水平。因此，长石质瓷和玻璃陶瓷中观察到的高β剂量水平主要归因于这些样本中天然存在的（40）K。尽管测量值低于推荐限值，但结果表明佩戴假牙的患者所受剂量水平高于其他人群。氧化铝基和氧化锆基陶瓷可能是一种有前景的替代材料，因为它们的β剂量率通常低于传统陶瓷材料。然而，剂量测定结果表明样品基质中存在放射性核素分布不均匀的簇团，而且其结构性能仍不合适，这就需要对这些材料进行进一步优化。
