title: Catalase and sodium fluoride mediated rehabilitation of enamel bleached with 37% hydrogen peroxide.
abstract: BACKGROUND
  Bleaching agents bring about a range of unwanted changes in the physical structure of enamel which needs to be restored qualitatively and timely. Catalase being an antioxidant ensures the effective removal of free radicals and improvement in fluoride mediated remineralization from the enamel microstructure which if retained may harm the integrity and affect the hardness of enamel.
  
  
  METHODS
  Thirty freshly extracted incisors were sectioned to 6 slabs which were divided into 5 groups: Group A, control; Group B, treatment with 37% hydrogen peroxide (HP); Group C, treatment with 37% HP and catalase, Group D, treatment with 37% HP and 5% sodium fluoride application, Group E, treatment with 37% HP followed by catalase and 5% sodium fluoride. Scanning electron microscope and microhardness analysis were done for all slabs. One-way ANOVA test was applied among different groups.
  
  
  RESULTS
  Vicker's microhardness number (VHN) of Group B and C was significantly lower. No significant difference between VHN of Group B and C. VHN of Group D was significantly higher than Group A, B, and C; but significantly lower than Group E. VHN of Group E was significantly higher than any other experimental group. One-way ANOVA revealed a highly significant P value (P = 0.0001) and so Tukey's post-hoc Test for the group comparisons was employed.
  
  
  CONCLUSIONS
  Subsequent treatment of bleached enamel with catalase and fluoride varnish separately results in repairing and significantly increasing the microhardness.
authors.affiliation: Department of Pedodontics and Preventive Dentistry, RKDF Dental College and Research Centre, Bhopal, Madhya Pradesh, India.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Thakur
authors.forename: Anand L
authors.initials: AL
authors.lastname: Shigli
authors.forename: Divya
authors.initials: D
authors.lastname: Sharma
authors.forename: Gagan
authors.initials: G
authors.lastname: Thakur
mesh_terms: D002374:Catalase / Q000494:pharmacology*; D003743:Dental Enamel / Q000187:drug effects*; D006244:Hardness; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D066298:In Vitro Techniques; D007180:Incisor; D008855:Microscopy, Electron, Scanning; D012969:Sodium Fluoride / Q000494:pharmacology*; D013499:Surface Properties; D014073:Tooth Bleaching / Q000009:adverse effects*; D017001:Tooth Demineralization / Q000139:chemically induced*; D014089:Tooth Remineralization / Q000379:methods*
chemical_list: D012969:Sodium Fluoride; D006861:Hydrogen Peroxide; D002374:Catalase