title: Evaluation of the cytotoxicity of elastomeric ligatures after sterilisation with 0.25% peracetic acid.
abstract: BACKGROUND
  Sterilisation using peracetic acid (PAA) has been advocated for orthodontic elastic bands. However, cane-loaded elastomeric ligatures can also become contaminated during processing, packaging, and manipulation before placement in the oral cavity and are therefore susceptible, and possible causes, of cross-contamination.
  
  
  OBJECTIVE
  To test the hypothesis that 0.25% peracetic acid (PAA), following the sterilisation of elastomers, influences the cytotoxicity of elastomeric ligatures on L929 cell lines.
  
  
  METHODS
  Four hundred and eighty silver elastomeric ligatures were divided into 4 groups of 120 ligatures to produce, Group TP (latex natural, bulk pack, TP Orthodontics), Group M1 (Polyurethane, bulk pack, Morelli), Group M2 (Polyurethane, cane-loaded, Morelli) and Group U (Polyurethane, cane-loaded, Uniden). Of the 120 ligatures in each group, 100 were sterilised in 0.25% PAA at time intervals (N = 20) of 1 hour, 2 hours, 3 hours, 4 hours and 5 hours. The 20 remaining elastomeric ligatures in each group were not sterilised and served as controls. Cytotoxicity was assessed using L929 cell lines and a dye-uptake method. Analysis of variance (ANOVA), followed by the Tukey post hoc test (p < 0.05) determined statistical relevance.
  
  
  RESULTS
  There was a significant difference between TP, Morelli and Uniden elastomerics (p < 0.05), but no difference between the two types of Morelli elastomerics at the 1 hour time interval. In addition, there was a significant difference between Group CC and the other groups assessed, except between Groups CC and TP at the 1 hour time interval. The non-sterilised elastomeric ligatures showed similar cell viability to that observed after 1 hour of standard sterilisation.
  
  
  CONCLUSIONS
  PAA did not significantly influence the cytotoxicity of elastomeric ligatures after a sterilisation time of 1 hour and is therefore recommended for clinical use.
authors.affiliation: State University of Sudoeste da Bahia, UESB, Brazil. matheuspithon@gmail.com
authors.forename: Matheus Melo
authors.initials: MM
authors.lastname: Pithon
authors.affiliation: Federal University of Campina Grande, UFCG, Brazil.
authors.forename: Rogerio Lacerda
authors.initials: RL
authors.lastname: dos Santos
authors.affiliation: Central Navy Dental Clinic, Rio de Janeiro, Brazil.
authors.forename: Renata Lima Pasini
authors.initials: RL
authors.lastname: Judice
authors.affiliation: Central Navy Dental Clinic, Rio de Janeiro, Brazil.
authors.forename: Paulo Sergio
authors.initials: PS
authors.lastname: de Assuncao
authors.affiliation: Central Navy Dental Clinic, Rio de Janeiro, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Restle
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents; D019551:Dental Disinfectants / Q000737:chemistry / Q000627:therapeutic use*; D020724:Elastomers / Q000737:chemistry / Q000633:toxicity*; D005347:Fibroblasts / Q000187:drug effects; D007840:Latex / Q000737:chemistry / Q000633:toxicity; D008422:Materials Testing; D009499:Neutral Red; D009967:Orthodontic Appliances; D010463:Peracetic Acid / Q000737:chemistry / Q000627:therapeutic use*; D011140:Polyurethanes / Q000737:chemistry / Q000633:toxicity; D051381:Rats; D013242:Sterilization / Q000379:methods*; D013997:Time Factors
chemical_list: D004396:Coloring Agents; D019551:Dental Disinfectants; D020724:Elastomers; D007840:Latex; D011140:Polyurethanes; D009499:Neutral Red; D010463:Peracetic Acid