title: Comparative evaluation of salivary bisphenol A levels in patients wearing vacuum-formed and Hawley retainers: An in-vivo study.
abstract: BACKGROUND
  The aims of the study were to evaluate and compare the bisphenol A (BPA) levels in saliva in patients using vacuum-formed retainers or Hawley retainers.
  
  
  METHODS
  Forty-five patients who had completed their fixed orthodontic treatment and were entering the retention phase were randomly allocated into 1 of 3 groups: vacuum-formed retainer, Hawley retainer fabricated by heat cure, and Hawley retainer fabricated by chemical cure. Saliva samples were collected immediately before placement, within 1 hour after placement, 1 week and 1 month after placement. Statistical analyses were performed by using 2-way analysis of variance and post-hoc multiple-comparisons Tukey HSD tests.
  
  
  RESULTS
  Statistically significant BPA levels in saliva were found for all groups (P ≤0.05). The highest levels were noted in the vacuum-formed retainer group, followed by Hawley retainers fabricated by chemical cure; the lowest levels were found with Hawley retainers fabricated by heat cure.
  
  
  CONCLUSIONS
  With many options available for removable retainers, clinicians should consider the BPA release from these retainers; a Hawley retainer fabricated by heat cure is a favorable choice.
authors.affiliation: Department of Orthodontics, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai, India.
authors.forename: Akila Srinivasan
authors.initials: AS
authors.lastname: Raghavan
authors.affiliation: Department of Orthodontics, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai, India.
authors.forename: Haritha
authors.initials: H
authors.lastname: Pottipalli Sathyanarayana
authors.affiliation: Department of Orthodontics, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai, India. Electronic address: vignesh.k@sriramachandra.edu.in.
authors.forename: Vignesh
authors.initials: V
authors.lastname: Kailasam
authors.affiliation: Department of Orthodontics, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai, India.
authors.forename: Sridevi
authors.initials: S
authors.lastname: Padmanabhan
mesh_terms: D001559:Benzhydryl Compounds / Q000032:analysis*; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D016382:Orthodontic Appliance Design; D018704:Orthodontic Retainers; D010636:Phenols / Q000032:analysis*; D012463:Saliva / Q000737:chemistry*; D014618:Vacuum; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D010636:Phenols; C006780:bisphenol A; D000098826:Bisphenol A Compounds