Hanson Mark, Lobner Doug
Department of Biomedical Sciences, School of Dentistry, Marquette University, 561 N. 15th Street, Room 426, Milwaukee, WI 53201, USA.
Am J Orthod Dentofacial Orthop. 2004 Jul;126(1):65-70. doi: 10.1016/j.ajodo.2003.07.006.
Although the toxicity of many dental materials has been thoroughly investigated, the toxicity of orthodontic elastic materials has not been extensively tested. We evaluated the neurotoxicity of 3 latex and 3 nonlatex orthodontic elastics in murine cerebral cortical cell cultures. Standard-sized pieces of each material from 3 manufacturers (American, Masel, and GAC) were placed on culture well inserts, allowing the material to be exposed to the culture bathing media without causing physical disruption of the cells. Cell death was quantified by assaying the release of the cytosolic enzyme lactate dehydrogenase. Exposure of cortical cultures to the nonlatex elastics did not cause significant neuronal death, but exposure to each of the latex elastics resulted in significant neuronal death. The neuronal death induced by each of the latex elastics was blocked by adding the metal chelator, EDTA (calcium disodium ethylenediaminetetraacetate). Because many latexes use zinc-containing compounds in the prevulcanization process, and the death induced had characteristics similar to zinc-induced neuronal death, it seems likely that the toxicity of latex elastics was mediated by zinc release. Because ingestion of zinc is not a health risk, the results suggest that, in spite of the finding that latex elastics have higher in vitro cytotoxicity than nonlatex elastics, the use of latex elastics in orthodontics is acceptable.
尽管许多牙科材料的毒性已得到充分研究，但正畸弹性材料的毒性尚未得到广泛测试。我们在小鼠大脑皮质细胞培养物中评估了3种乳胶和3种非乳胶正畸弹性材料的神经毒性。从3家制造商（美国、马塞尔和GAC）获取的每种材料的标准尺寸片材被放置在培养孔插入物上，使材料暴露于培养浴液中而不会对细胞造成物理破坏。通过检测胞质酶乳酸脱氢酶的释放来量化细胞死亡。将皮质培养物暴露于非乳胶弹性材料不会导致显著的神经元死亡，但暴露于每种乳胶弹性材料都会导致显著的神经元死亡。添加金属螯合剂乙二胺四乙酸二钠（EDTA）可阻断每种乳胶弹性材料诱导的神经元死亡。由于许多乳胶在预硫化过程中使用含锌化合物，且诱导的死亡具有与锌诱导的神经元死亡相似的特征，乳胶弹性材料的毒性似乎是由锌释放介导的。由于摄入锌对健康没有风险，结果表明，尽管发现乳胶弹性材料在体外的细胞毒性高于非乳胶弹性材料，但在正畸中使用乳胶弹性材料是可以接受的。
