title: In situ effect of enamel salivary exposure time and type of intraoral appliance before an erosive challenge.
abstract: OBJECTIVE
  This study tested the effect of enamel salivary exposure time prior to an acid challenge (30 min, 1, 2, or 12 h) and type of intraoral appliance (palatal or mandibular) on initial erosion.
  
  
  METHODS
  After initial surface hardness evaluation, enamel blocks (n = 340) were randomly divided into groups and volunteers (n = 20). The control group was not exposed to saliva previously to the erosive challenge. The volunteers wore palatal and mandibular appliances simultaneously. After salivary exposure, the blocks were subjected to acid exposure by immersion in hydrochloric acid (0.01 M, pH 2.3) for 30 s. Then, the enamel surface hardness was evaluated. Data were analyzed using ANOVA, Kruskal-Wallis and Tukey's test (p < 0.05).
  
  
  RESULTS
  No difference was observed on percent surface hardness change (% SHC) in the enamel blocks between the types of intraoral appliances. Exposure to saliva for 30 min and 1 h promoted similar enamel resistance to the erosive attack, which was similar to the control group for both appliances. Blocks exposed to saliva for 2 h showed less hardness loss when compared to 30 min. Keeping the blocks in saliva during 12-h overnight resulted in similar percentage of enamel hardness loss compared to 2 h.
  
  
  CONCLUSIONS
  A 2-hour in situ exposure to saliva is adequate to promote partial protection against initial erosive lesions, independently of the type of intraoral appliance used.
  
  
  CONCLUSIONS
  This finding will help researchers in the development of erosion studies, which will provide information for dentists to offer a better treatment for erosion.
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru School of Dentistry, University of São Paulo, Alameda Dr. Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-101, Brazil.
authors.forename: Fernanda Lyrio
authors.initials: FL
authors.lastname: Mendonça
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru School of Dentistry, University of São Paulo, Alameda Dr. Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-101, Brazil.
authors.forename: Maisa Camillo
authors.initials: MC
authors.lastname: Jordão
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru School of Dentistry, University of São Paulo, Alameda Dr. Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-101, Brazil.
authors.forename: Franciny Querobim
authors.initials: FQ
authors.lastname: Ionta
authors.affiliation: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Marília Afonso Rabelo
authors.initials: MAR
authors.lastname: Buzalaf
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru School of Dentistry, University of São Paulo, Alameda Dr. Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-101, Brazil.
authors.forename: Heitor Marques
authors.initials: HM
authors.lastname: Honório
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Linda
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Public Health, Bauru School of Dentistry, University of São Paulo, Alameda Dr. Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-101, Brazil. daniriosop@yahoo.com.br.
authors.forename: Daniela
authors.initials: D
authors.lastname: Rios
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D003743:Dental Enamel / Q000737:chemistry* / Q000187:drug effects; D005260:Female; D006245:Hardness Tests; D006801:Humans; D006851:Hydrochloric Acid; D008297:Male; D009967:Orthodontic Appliances; D012463:Saliva / Q000737:chemistry* / Q000502:physiology; D016037:Single-Blind Method; D013499:Surface Properties; D013997:Time Factors; D014077:Tooth Erosion / Q000517:prevention & control*
chemical_list: D006851:Hydrochloric Acid
keywords: Acquired enamel pellicle formation; Dental enamel; Saliva; Tooth erosion; Tooth remineralization