title: Effect of 7.5% hydrogen peroxide containing remineralizing agents on hardness, color change, roughness and micromorphology of human enamel.
abstract: OBJECTIVE
  To determine the microhardness, color change, surface roughness, and micromorphology of tooth enamel submitted to bleaching treatment with 7.5% hydrogen peroxide (HP) with added calcium, amorphous calcium phosphate, sodium fluoride (NaF), and hydroxyapatite (HA).
  
  
  METHODS
  80 enamel slabs were used (n = 10). Three commercial agents [Pola Day 7.5%, Day White ACP 7.5% (DW-ACP), and White Class Calcium 7.5% (WC-Calcium)], three experimental (7.5% HP+NaF, 7.5% HP+HA, and 7.5% PH+NaF+HA), a positive control (with HP), and a negative control (without HP) groups were assessed. The commercial products were applied according to manufacturers' recommendations and the experimental ones were applied for 1.5 hours daily. During and after treatment, specimens were stored in artificial saliva. Tests were performed at baseline, 7, 14, 21, 28, and 35 days. Data were analyzed by ANOVA and Tukey's test (α = 0.05).
  
  
  RESULTS
  DW-ACP presented lower microhardness and HP+HA presents the highest values (P < 0.05); only the experimental group presented color change similar to the commercial agents (P > 0.05). Overall, roughness increased with time (P < 0.05) and porosities, and deposition of crystalline structures in groups HP+HA and HP+NaF+HA were noted. The HP+HA agent was capable of reducing the loss of enamel microhardness due to bleaching and also present color change similar to the commercial products.
authors.forename: Robson Tetsuo
authors.initials: RT
authors.lastname: Sasaki
authors.forename: Anderson
authors.initials: A
authors.lastname: Catelan
authors.forename: Eduardo dos Santos
authors.initials: Edos S
authors.lastname: Bertoldo
authors.forename: Paulo César
authors.initials: PC
authors.lastname: Venâncio
authors.forename: Francisco Carlos
authors.initials: FC
authors.lastname: Groppo
authors.forename: Gláucia Maria Bovi
authors.initials: GM
authors.lastname: Ambrosano
authors.forename: Giselle M
authors.initials: GM
authors.lastname: Marchi
authors.forename: Débora Alves Nunes Leite
authors.initials: DA
authors.lastname: Lima
authors.forename: Flávio Henrique Baggio
authors.initials: FH
authors.lastname: Aguiar
mesh_terms: D002118:Calcium / Q000627:therapeutic use; D002130:Calcium Phosphates / Q000627:therapeutic use; D003116:Color; D003461:Crystallography; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D017886:Durapatite / Q000627:therapeutic use; D006244:Hardness; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000627:therapeutic use*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D012464:Saliva, Artificial / Q000737:chemistry; D012969:Sodium Fluoride / Q000627:therapeutic use; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D014089:Tooth Remineralization / Q000379:methods*
chemical_list: D002130:Calcium Phosphates; D012464:Saliva, Artificial; C519480:amorphous calcium phosphate; D012969:Sodium Fluoride; D017886:Durapatite; D006861:Hydrogen Peroxide; D002118:Calcium