title: Evaluation of the cytotoxicity of fiber reinforced composite bonded retainers and flexible spiral wires retainers in simulated high and low cariogenic environments.
abstract: OBJECTIVE
  The aim of this study was to evaluate the cytotoxic effects of fiber reinforced composite bonded retainers in comparison with flexible spiral wires (FSWs) under high and low cariogenic-simulated environments using human oral fibroblasts.
  
  
  METHODS
  Four types of bonded retainers were evaluated: (1) reinforced with glass fibers: Interlig (Angelus), (2) reinforced with polyethylene fibers: Connect (Kerr), (3) reinforced with quartz fibers: Quartz Splint UD (RTD), and (4) FSW. Twenty specimens of each sample group were prepared with the same surface area and halved. Next, half of them were placed in a high cariogenic environment 60 min in 10% lactic acid 3 times a day and remained in Fusayama Meyer artificial saliva for the rest of the day) and the other half were placed in a low cariogenic environment 20 min in 10% lactic acid 3 times a day and remained in Fusayama Meyer artificial saliva for the rest of the day) for 1, 7 and 30 days. Cell viability was assessed by MTT assay. Data were analyzed using SPSS software (α =0.05).
  
  
  RESULTS
  During the 1(st) month, cytotoxicity reduced gradually. In the low cariogenic-simulated environment, the cytotoxicity of all of the groups were reported to be mild at day 30 and the difference between them was significant (P = 0.016). In the same period in the high cariogenic-simulated environment, the cytotoxicity of Connect and Quartz Splint was mild, and they had lower cytotoxicity than the other groups. Meanwhile, Interlig had moderate (52%) and FSW had severe cytotoxicity (22%) and the difference between the groups was also significant (P = 0.000).
  
  
  CONCLUSIONS
  FSW retainers are not recommended in those at high-risk for dental caries. However, in those at low-risk, there is no difference from the standpoint of cytotoxicity.
authors: Dental Research Center, Department of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Arezoo
authors: A
authors: Jahanbin
authors: Dental Research Center, Department of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Mostafa
authors: M
authors: Shahabi
authors: Dental Research Center, Department of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Farzaneh
authors: F
authors: Ahrari
authors: Department of Orthodontics, School of Dentistry, Bojnord University of Medical Sciences, Bojnord, Iran.
authors: Yasaman
authors: Y
authors: Bozorgnia
authors: Immunology Research Center, Immunogenetic and Tissue Culture Department, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Arezoo
authors: A
authors: Shajiei
authors: Dental Research Center, Department of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Hooman
authors: H
authors: Shafaee
authors: Bu-Ali Research Institute, Immunogenetic and Tissue Culture Department, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Jalil Tavakkol
authors: JT
authors: Afshari
keywords: Cell viability; cytotoxicity; fiber reinforced composite; retainer