title: [Cytotoxicitic detection of laser welding between NiTi shape memory alloy and stainless steel in vitro].
abstract: OBJECTIVE
  To investigate the cytotoxicity of laser-welded nickel titanium (NiTi) and stainless steel composite archwire.
  
  
  METHODS
  The NiTi and stainless steel composite archwire (CoAW) laser-welded with pure copper inrerplayer was studied with methyl thiazolyl tetrazolium (MTT) test in vitro. The cytotoxicity of CoAW was compared with stainless steel archwire and NiTi archwire. Two tests were carried out. Test 1: the immersed solution of CoAW was diluted to five grades (50%, 40%, 30%, 20%, 10%). The cytotoxicity in vitro of these agents was assayed on murine fibroblast cell L929 line with MTT test at 24 and 48 hours. Test 2: the immeresed solution of CoAW, NiTi archwires and stainless steel archwires was diluted to four grads (100%, 75%, 50%, 25%). The cytotoxity of three kinds of material was compared at 48 hours.
  
  
  RESULTS
  The results of all samples revealed level 0-1 cytotoxicity. In test 1, the same grade solution optical density (except 20%) at 24 hours was statistically lower than at 48 hours. In test 2, the optical density of CoAW solution (1.964 ± 0.122, 2.084 ± 0.056, 2.056 ± 0.071, 2.096 ± 0.050) was statistically lower than the same grade solution of stainless steel archwire (2.168 ± 0.091, 2.227 ± 0.160, 2.302 ± 0.052, 2.301 ± 0.060) and NiTi archwire (2.138 ± 0.105, 2.262 ± 0.050, 2.271 ± 0.082, 2.294 ± 0.056) (P < 0.05).
  
  
  CONCLUSIONS
  The MTT test of CoAW in vitro showed that cytotoxicity was related to concentration and time. The cytotoxicity of the CoAW was more serious than that of stainless steel and NiTi archwires. However, CoAW belonged to secure rang of material toxicity reaction.
authors: Department of Orthodontics, School of Stomatology, Jilin University, Changchun 130021, China.
authors: Wenwen
authors: W
authors: Yu
authors: Department of Orthodontics, School of Stomatology, Jilin University, Changchun 130021, China.
authors: Chao
authors: C
authors: Zhang
authors: Department of Orthodontics, School of Stomatology, Jilin University, Changchun 130021, China.
authors: Bing
authors: B
authors: Zhang
authors: Department of Orthodontics, School of Stomatology, Jilin University, Changchun 130021, China.
authors: Jiming
authors: J
authors: Liu
authors: Department of Orthodontics, School of Stomatology, Jilin University, Changchun 130021, China. Email: xinhuasun8@163.com.
authors: Xinhua
authors: X
authors: Sun
mesh_terms: D000818:Animals; D003300:Copper; D066298:In Vitro Techniques; D007834:Lasers; D051379:Mice; D009532:Nickel / Q000633:toxicity*; D009969:Orthodontic Wires; D013193:Stainless Steel; D014025:Titanium / Q000633:toxicity*; D014896:Welding
chemical_list: C040654:titanium nickelide; D013193:Stainless Steel; D003300:Copper; D009532:Nickel; D014025:Titanium