Effect of N-acetyl cysteine on orthodontic primers cytotoxicity

Vincenzo D'Antò, Gianrico Spagnuolo, Helmut Schweikl, Sandro Rengo, Luigi Ambrosio, Roberto Martina, Rosa Valletta

Research output: Contribution to journalArticlepeer-review


Objectives: The aims of this study were to evaluate the cytotoxicity of four orthodontic primers, including two hydrophilic and two hydrophobic materials, and to investigate the role of the reactive oxygen species (ROS) in induced cell damage. Moreover, the effects of the anti-oxidant N-acetyl cysteine (NAC) on primers toxicity was analyzed. Methods: Human gingival fibroblasts (HGF) were exposed to different concentrations of primers (0-0.25 mg/ml) in the presence or absence of NAC, and the cytotoxicity was assessed by the MTT assay, while cell death was quantified by flow cytometry after propidium iodide staining. The increase in the induced ROS levels was detected by flow cytometry measuring the fluorescence of the oxidation-sensitive dye 2′,7′- dichlorofluorescein diacetate (DCFH-DA). Results: All materials decreased cell viability in a dose-related manner after a 24 h exposure period. Cytotoxicity of orthodontic primers based on concentrations which caused a 50% decrease in cell viability (TC50) in HGF was ranked as follows (median values): Eagle Fluorsure (0.078 mg/ml) > Transbond XT (0.081 mg/ml) > Transbond MIP (0.128 mg/ml) > Ortho solo (0.130 mg/ml). Moreover, in HGF cells, all materials induced a dose-dependent increase in ROS levels compared to untreated cells. Incubation of HGF with NAC significantly reduced ROS production and decreased the cell damage and cytotoxicity caused by all materials tested (p <0.001). Significance: Our results suggested that hydrophilic primers were less cytotoxic than hydrophobic materials. Moreover, we demonstrated a major role of ROS in the induction of cell death since the antioxidant N-acetyl cysteine was able to prevent cell damage induced by all materials tested.

Original languageEnglish
Pages (from-to)180-186
Number of pages7
JournalDental Materials
Issue number2
Publication statusPublished - Feb 2011


  • Cytotoxicity
  • N-acetyl cysteine
  • Orthodontic adhesives
  • Reactive oxygen species

ASJC Scopus subject areas

  • Dentistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Medicine(all)


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