title: Influence of peroxide treatment on bovine enamel surface--cross-sectional analysis.
abstract: Carbamide peroxide and hydrogen peroxide are used as the main agents in vital tooth bleaching. In this study, the influence of peroxide treatment on cross-sectional morphology and mechanical property was investigated. A 3 x 5-mm window of enamel on the labial surface of a bovine tooth was exposed to immersion in 10% or 30% carbamide peroxide or hydrogen peroxide for 30 or 180 min. After immersion, the cross-sectional structure of each specimen was examined by nanoindentation and SEM. Nanohardness in the enamel showed a decrease at 2 microm below the surface, but none at 50 microm. High concentrations of peroxide caused erosion to a depth of 5 microm below the surface. In conclusion, decrease in nanohardness and change in morphology were limited to an area less than 50 microm below the surface, regardless of either concentration of peroxide or period of immersion.
authors: Department of Dental Materials Science, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba 261-8502, Japan.
authors: Toshiaki
authors: T
authors: Ushigome
authors: Shinji
authors: S
authors: Takemoto
authors: Masayuki
authors: M
authors: Hattori
authors: Masao
authors: M
authors: Yoshinari
authors: Eiji
authors: E
authors: Kawada
authors: Yutaka
authors: Y
authors: Oda
mesh_terms: D019412:Anatomy, Cross-Sectional; D000818:Animals; D001696:Biomechanical Phenomena; D002118:Calcium / Q000032:analysis; D000077463:Carbamide Peroxide; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D003747:Dental Enamel Solubility / Q000187:drug effects; D004338:Drug Combinations; D006244:Hardness; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000494:pharmacology; D007101:Immersion; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016877:Oxidants / Q000008:administration & dosage / Q000494:pharmacology*; D010545:Peroxides / Q000008:administration & dosage / Q000494:pharmacology*; D010758:Phosphorus / Q000032:analysis; D013997:Time Factors; D014073:Tooth Bleaching; D014077:Tooth Erosion / Q000139:chemically induced / Q000473:pathology; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D010758:Phosphorus; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide; D002118:Calcium