title: Toothbrushing abrasion susceptibility of enamel and dentin bleached with calcium-supplemented hydrogen peroxide gel.
abstract: The objective of this study was to evaluate enamel and dentin susceptibility to toothbrushing abrasion, after bleaching with 7.5% hydrogen peroxide (HP) gel supplemented or not with 0.5% calcium gluconate (Ca). Toothbrushing was performed immediately and 1h after bleaching, with two suspensions (high and low abrasivity). Bovine enamel and dentin specimens were divided into 12 groups (n=10) according to the bleaching gel (with and without Ca), slurry abrasivity (high or low) and elapsed time after bleaching (immediately and after 1h). As control, a group was not bleached, but abraded. The treatment cycle (7 d) consisted of bleaching (1h) and toothbrushing (135 strokes/day) immediatelly or after 1h of artificial saliva exposure. Surface roughness and surface loss (μm) were measured by profilometry and analysed by three-way ANOVA (5%). Surface roughness means were significantly influenced by slurry abrasivity (p<0.0001). For enamel loss, significant triple interaction was observed (p<0.0001). HP-bleached groups and immediately brushed with high-abrasive slurry exhibited increased loss (1.41±0.14) compared to other groups (μm). Control and HP+Ca-bleached groups brushed after 1h with low abrasive slurry presented the lowest loss (0.21±0.03/0.27±0.02). For dentin loss, significant interaction was observed for bleaching and interval factors (p<0.001). 7.5%HP-bleached groups and immediately brushed showed significantly higher loss (8.71±2.45) than the other groups. It was concluded that surface roughness increased when high abrasive was used, independently of bleaching. 7.5%HP increased enamel and dentin loss, mainly with high abrasive slurries. Calcium supplementation of bleaching gel reduced surface loss. Additionally, in order to minimize tooth wear susceptibility, it is recommended to delay brushing after bleaching.
  
  
  
  After bleaching gel application, postponing toothbrushing is recommended, as well as brushing with low abrasive dentifrices. Additionally, supplementation of hydrogen peroxide gel with calcium-based remineralizing agent potentially reduces tooth loss after abrasion.
authors.affiliation: Department of Restorative Dentistry, Univ. Estadual Paulista, Av. Eng. Francisco José Longo 777, Jardim São Dimas, São José dos Campos, SP, 12245-000, Brazil. Electronic address: alessandra@fosjc.unesp.br.
authors.forename: A B
authors.initials: AB
authors.lastname: Borges
authors.affiliation: Department of Restorative Dentistry, Univ. Estadual Paulista, Av. Eng. Francisco José Longo 777, Jardim São Dimas, São José dos Campos, SP, 12245-000, Brazil.
authors.forename: L F T F
authors.initials: LF
authors.lastname: Santos
authors.affiliation: Department of Restorative Dentistry, Univ. Estadual Paulista, Av. Eng. Francisco José Longo 777, Jardim São Dimas, São José dos Campos, SP, 12245-000, Brazil.
authors.forename: M G
authors.initials: MG
authors.lastname: Augusto
authors.affiliation: Department of Restorative Dentistry, Univ. Estadual Paulista, Av. Eng. Francisco José Longo 777, Jardim São Dimas, São José dos Campos, SP, 12245-000, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Bonfiette
authors.affiliation: Oral Health Research Institute, Department of Preventive and Community Dentistry, Indiana University School of Dentistry, Indianapolis, IN, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Hara
authors.affiliation: Department of Restorative Dentistry, Univ. Estadual Paulista, Av. Eng. Francisco José Longo 777, Jardim São Dimas, São José dos Campos, SP, 12245-000, Brazil.
authors.forename: C R G
authors.initials: CR
authors.lastname: Torres
mesh_terms: D000818:Animals; D002118:Calcium; D002417:Cattle; D003743:Dental Enamel; D003804:Dentin; D006861:Hydrogen Peroxide; D014072:Tooth Abrasion; D014073:Tooth Bleaching; D014099:Toothbrushing
chemical_list: D006861:Hydrogen Peroxide; D002118:Calcium
keywords: Dentin; Enamel; Hydrogen peroxide; Tooth abrasion; Tooth bleaching