title: Evaluation of the genotoxicity and cytotoxicity in the buccal epithelial cells of patients undergoing orthodontic treatment with three light-cured bonding composites by using micronucleus testing.
abstract: OBJECTIVE
  This study evaluated the cytotoxicity and genotoxicity of fixed orthodontic treatment with three different light-cured orthodontic bonding composites by analyzing micronucleus (MN) formation in the buccal mucosa during a 6-month period.
  
  
  METHODS
  Thirty healthy volunteers were selected from consecutive patients referred for orthodontic treatment. Equilibrium 2 brackets and molar tubes (Dentaurum) were bonded with three different light-cured orthodontic bonding composites-Transbond XT (3M Unitek), Kurasper F (Kuraray Europe), or GrenGloo (Ormco Corporation)- to all teeth in both arches. Exfoliated buccal epithelial cells were scraped from the middle part of the inner cheeks with sterile cement spatulas before treatment and at 1, 3, and 6 months after treatment. MNs and nuclear alterations, such as karyorrhexis (KR), karyolysis (KL), and binucleated cells (BNs), were scored under a light microscope. Repeated measure ANOVA was used to calculate statistical differences in degenerative nuclear abnormalities.
  
  
  RESULTS
  MN rates did not significantly differ among different time points within the same cell type (p > 0.05). In contrast, the number of BNs in buccal epithelial cells significantly increased in all composite groups (p < 0.01, Transbond XT; p < 0.001, Kurasper F and GrenGloo). KL frequency significantly increased between the beginning and end of the study in the Kurasfer F (0.80 ± 0.79 to 1.90 ± 1.10; p < 0.05) and GrenGloo (1.30 ± 1.06 to 2.40 ± 1.08; p < 0.05) groups.
  
  
  CONCLUSIONS
  After 6 months of fixed orthodontic treatment with different light-cured composites, morphological signs of cytotoxicity were observed but genotoxic effects were absent.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Inonu University, Malatya, Turkey.
authors.forename: Ebubekir
authors.initials: E
authors.lastname: Toy
authors.affiliation: Department of Medical Biology and Genetics, Faculty of Medicine, Inonu University, Malatya, Turkey.
authors.forename: Sengul
authors.initials: S
authors.lastname: Yuksel
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Pamukkale University, Denizli, Turkey.
authors.forename: Firat
authors.initials: F
authors.lastname: Ozturk
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Inonu University, Malatya, Turkey.
authors.forename: Orhan Hakki
authors.initials: OH
authors.lastname: Karatas
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Inonu University, Malatya, Turkey.
authors.forename: Muhammet
authors.initials: M
authors.lastname: Yalcin
keywords: Buccal epithelial cells; Cytotoxicity; Genotoxicity; Micronucleus test; Orthodontic composites