title: Effects of toothbrushing with fluoride abrasive and whitening dentifrices on both unbleached and bleached human enamel surface in terms of roughness and hardness: an in vitro study.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate the surface roughness and hardness of both unbleached and bleached (opalescence; 10% carbamide peroxide) human enamel brushed with water (without dentifrice), fluoride abrasive dentifrice (Colgate Total) and whitening dentifrice (Natural White).
  
  
  METHODS
  Human enamel samples were obtained from third molars and randomly divided into five groups (n = 8): G1 - Control (brushed with water without dentifrice), G2 - Colgate Total (fluoride abrasive dentifrice), G3 - Natural White (whitening dentifrice), G4 - Opalescence (10% carbamide peroxide) and then brushed with Colgate Total, G5 - Opalescence (10% carbamide peroxide) and then brushed with Natural White. Bleaching regimen was applied according to manufacturers' instructions. The brushing process was performed with a modified Nyffenegger's brushing machine. Surface roughness was analyzed with a profilometer. Microhardness testing was performed with a Brinell hardness tester.
  
  
  RESULTS
  Results were statistically analyzed by Kruskal-Wallis, one-way ANOVA analysis and Mann-Whitney U, Wilcoxon matched-pairs signed-ranks tests. There were significant differences in surface roughness values for all groups, which showed an increase in roughness (p < 0.05). When the bleaching treatment combined with brushing with whitening dentifrice was performed (G5), there was a significant decrease in hardness values (p < 0.05). The other groups (G1, G2, G3, G4) showed no significant hardness differences (p > 0.05).
  
  
  CONCLUSIONS
  It was concluded that toothbrushing procedures increased the enamel surface roughness, and that bleaching regimen performed with cleaning treatment, through brushing with whitening dentifrice decreased hardness values.
  
  
  CONCLUSIONS
  When applied together, bleaching and cleaning treatments may alter the enamel surface roughness and hardness values.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry Hacettepe University, Ankara, Turkey.
authors.forename: Sukran
authors.initials: S
authors.lastname: Bolay
authors.forename: Filiz Yalcin
authors.initials: FY
authors.lastname: Cakir
authors.forename: Sevil
authors.initials: S
authors.lastname: Gurgan
mesh_terms: D000077463:Carbamide Peroxide; D002327:Cariostatic Agents / Q000627:therapeutic use*; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D003799:Dental Stress Analysis / Q000295:instrumentation; D003802:Dentifrices / Q000627:therapeutic use*; D005459:Fluorides / Q000627:therapeutic use*; D006244:Hardness; D006801:Humans; D006813:Humidity; D010545:Peroxides / Q000627:therapeutic use; D012824:Silicic Acid / Q000627:therapeutic use; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D058205:Tooth Bleaching Agents / Q000627:therapeutic use*; D014099:Toothbrushing / Q000295:instrumentation / Q000379:methods*; D014100:Toothpastes / Q000627:therapeutic use; D014508:Urea / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D002327:Cariostatic Agents; D003802:Dentifrices; D010545:Peroxides; D058205:Tooth Bleaching Agents; D014100:Toothpastes; C546060:hydrated silica gel-based toothpaste; D012824:Silicic Acid; D000077463:Carbamide Peroxide; D014508:Urea; D005459:Fluorides