Docent Unit of Integral Pediatric Dentistry, Faculty of Medicine, Dental Clinic, University of Murcia, Murcia, Spain.
Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):e115-22. doi: 10.1016/j.ajodo.2011.02.021.
The aims of this study were to determine the amounts of metallic ions that stainless steel, nickel-free, and titanium alloys release to a culture medium, and to evaluate the cellular viability and DNA damage of cultivated human fibroblasts with those mediums.
The metals were extracted from 10 samples (each consisting of 4 buccal tubes and 20 brackets) of the 3 orthodontic alloys that were submerged for 30 days in minimum essential medium. Next, the determination of metals was performed by using inductively coupled plasma mass spectrometry, cellular viability was assessed by using the tetrazolium reduction assay (MTT assay) (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide), and DNA damage was determined with the Comet assay. The metals measured in all the samples were Ti(47), Cr(52), Mn(55), Co(59), Ni(60), Mo(92), Fe(56), Cu(63), Zn(66), As(75), Se(78), Cd(111), and Pb(208).
The cellular viability of the cultured fibroblasts incubated for 7 days with minimum essential medium, with the stainless steel alloy submerged, was close to 0%. Moreover, high concentrations of titanium, chromium, manganese, cobalt, nickel, molybdenum, iron, copper, and zinc were detected. The nickel-free alloy released lower amounts of ions to the medium. The greatest damage in the cellular DNA, measured as the olive moment, was also produced by the stainless steel alloy followed by the nickel-free alloy. Conversely, the titanium alloy had an increased cellular viability and did not damage the cellular DNA, as compared with the control values.
The titanium brackets and tubes are the most biocompatible of the 3 alloys studied.
本研究旨在确定不锈钢、无镍和钛合金释放到培养基中的金属离子量，并评估这些培养基对培养的人成纤维细胞的细胞活力和 DNA 损伤。
将 3 种正畸合金的 10 个样本（每个样本由 4 个颊管和 20 个托槽组成）在最小必需培养基中浸泡 30 天，然后从这些样本中提取金属。接下来，采用电感耦合等离子体质谱法测定金属含量，采用噻唑蓝（MTT）还原试验（3-[4,5-二甲基噻唑-2-基]-2,5-二苯基四唑溴盐）评估细胞活力，采用彗星试验测定 DNA 损伤。对所有样本进行了 Ti(47)、Cr(52)、Mn(55)、Co(59)、Ni(60)、Mo(92)、Fe(56)、Cu(63)、Zn(66)、As(75)、Se(78)、Cd(111)和 Pb(208)等金属的测量。
与不锈钢合金浸泡的最小必需培养基孵育 7 天后培养的成纤维细胞的细胞活力接近 0%。此外，还检测到高浓度的钛、铬、锰、钴、镍、钼、铁、铜和锌。无镍合金向培养基中释放的离子较少。作为橄榄矩，细胞 DNA 受到的最大损伤也是由不锈钢合金产生的，其次是无镍合金。相反，与对照值相比，钛合金具有增加的细胞活力且不会损伤细胞 DNA。
在所研究的 3 种合金中，钛支架和托槽具有最高的生物相容性。
