title: Assessment of orthodontic biomaterials' cytotoxicity: an in vitro study on cell culture.
abstract: OBJECTIVE
  Orthodontists use various biomaterials such as molar bands, brackets, archwires, transpalatal archwires, facial masks and other auxiliary devices. One of the essential properties of these materials should be the biocompatibility. The aim of this study was to evaluate the biocompatibility of some orthodontic biomaterials like stainless steel archwires, brackets and NiTi (nickel-titanium alloy) coil springs.
  
  
  METHODS
  The studies were performed in vitro using human fibroblasts cultures on which the orthodontic materials were applied. The positive control was the copper amalgam. Readings of the cell reactions were performed at three and six days.
  
  
  RESULTS
  It was observed that the materials used in the study cause cell alterations of variable intensity. The metallic brackets represent an important cell stress factor causing shape changes. For the metallic brackets, a preferential tropism for different areas of the bracket was also obvious. We observed a preferential tropism for the areas between the NiTi coil spring spirals. For the stainless steel archwires, we observed at six days a decay of cell density and also a higher amount of cells near the archwire areas on which bends were performed.
  
  
  CONCLUSIONS
  All biomaterials analyzed in our study cause cellular changes of varying intensity without necessarily showing a cytotoxic character.
authors.affiliation: Department of Pedodontics-Orthodontics, Faculty of Dental Medicine, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania; ogodescu@yahoo.com.
authors.forename: Alina
authors.initials: A
authors.lastname: Sodor
authors.forename: Alexandru Simion
authors.initials: AS
authors.lastname: Ogodescu
authors.forename: Tudor
authors.initials: T
authors.lastname: Petreuş
authors.forename: Alina Maria
authors.initials: AM
authors.lastname: Şişu
authors.forename: Irina Nicoleta
authors.initials: IN
authors.lastname: Zetu
mesh_terms: D001672:Biocompatible Materials / Q000633:toxicity*; D002452:Cell Count; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D005347:Fibroblasts / Q000187:drug effects / Q000473:pathology*; D006801:Humans; D009967:Orthodontic Appliances / Q000009:adverse effects*; D018675:Toxicity Tests
chemical_list: D001672:Biocompatible Materials