title: Effect of fluoride therapies on the surface roughness of human enamel exposed to bleaching agents.
abstract: OBJECTIVE
  To evaluate in vitro the effect of fluoride therapies on the surface roughness of human dental enamel exposed to bleaching agents.
  
  
  METHODS
  Sixty-six specimens obtained from 33 third molars were centrally cut, mounted on acrylic resin supports, polished, and submitted to baseline surface roughness readings (RaB). Next, the specimens were distributed into 11 groups and exposed to one of the bleaching agents-16% carbamide peroxide (CP) or 35% hydrogen peroxide (HP)-and one of the fluoride therapies-0.05% NaF daily (DF); 0.2% NaF weekly (WF); 2% final topical fluoride (FTF); or 2% initial and final topical fluoride (IFTF). The positive control group specimens were exposed to neither bleaching agents nor fluoride therapies. The negative control group specimens were exposed to the bleaching agents but none of the fluoride therapies. After storage in artificial saliva for 7 days, final surface roughness readings (RaF) were taken. Percentage differences between RaB and RaF were analyzed by ANOVA and Tukey HSD tests at a P value of .05.
  
  
  RESULTS
  The bleaching agents CP and HP increased the surface roughness compared with the control group; FTF and IFTF reduced the surface roughness of enamel exposed to CP and HP; DF and WF did not reduce the surface roughness of enamel exposed to CP and HP.
  
  
  CONCLUSIONS
  Both bleaching agents tested increased the surface roughness of dental enamel, and both topical fluoride therapies were effective at reducing the increase in enamel surface roughness after bleaching.
authors.affiliation: Dental School, Pontifical Catholic University of Paraná (PUCPR), Paraná, Brazil.
authors.forename: Juliana Maria Habith
authors.initials: JM
authors.lastname: Martin
authors.forename: Janaina Bertoncelo
authors.initials: JB
authors.lastname: de Almeida
authors.forename: Edvaldo Antonio Ribeiro
authors.initials: EA
authors.lastname: Rosa
authors.forename: Paulo
authors.initials: P
authors.lastname: Soares
authors.forename: Vladja
authors.initials: V
authors.lastname: Torno
authors.forename: Rodrigo Nunes
authors.initials: RN
authors.lastname: Rached
authors.forename: Rui Fernando
authors.initials: RF
authors.lastname: Mazur
mesh_terms: D000704:Analysis of Variance; D000077463:Carbamide Peroxide; D003743:Dental Enamel / Q000187:drug effects*; D005460:Fluorides, Topical / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000009:adverse effects; D010545:Peroxides / Q000009:adverse effects; D012969:Sodium Fluoride / Q000494:pharmacology*; D018709:Statistics, Nonparametric; D013499:Surface Properties / Q000187:drug effects; D058205:Tooth Bleaching Agents / Q000009:adverse effects*; D014089:Tooth Remineralization / Q000379:methods*; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives
chemical_list: D005460:Fluorides, Topical; D010545:Peroxides; D058205:Tooth Bleaching Agents; D000077463:Carbamide Peroxide; D014508:Urea; D012969:Sodium Fluoride; D006861:Hydrogen Peroxide