Effect of peroxide-based bleaching agents on enamel ultimate tensile strength.
This study evaluated the effects of peroxide bleaching regimens on the ultimate tensile strength (UTS) of human enamel. A resin composite block was built-up on the bonded occlusal surface of 14 extracted, sound, erupted third molars to enable posterior preparation for the microtensile test. The bonded teeth were serially sectioned in a buccal-lingual direction into approximately 0.7-mm thick slices. Each slice was trimmed with a fine diamond bur to reduce the area of the buccal, internal slope of the cusps to a dumb-bell shape with a cross-sectional area of less than 1 mm2. The samples were randomly divided into seven groups (n = 10): unbleached control group and bleached groups treated with six bleaching regimens. The specimens were tested in tension at 0.5 mm/minute and the data were analyzed by ANOVA and Tukey test. Specimens from the control group presented 51.3 +/- 8.6 MPa, while the UTS of bleached enamel ranged from 22.0 +/- 5.6 to 36.3 +/- 9.1 MPa. All bleaching procedures significantly reduced enamel UTS (p < 0.05). Differences were also observed among treatments. The results suggested that bleaching regimens can significantly reduce enamel UTS.
University of Campinas, Piracicaba School of Dentistry, Department of Restorative Dentistry, Piracicaba, Brazil.
Alessandra Peres
AP
da Silva
Rogério
R
de Oliveira
Vanessa
V
Cavalli
César Augusto Galvão
CA
Arrais
Marcelo
M
Giannini
Ricardo Marins
RM
de Carvalho
D000704:Analysis of Variance; D000077463:Carbamide Peroxide; D003743:Dental Enamel / Q000737:chemistry / Q000187:drug effects*; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008964:Molar, Third / Q000737:chemistry / Q000187:drug effects; D010545:Peroxides / Q000494:pharmacology*; D013718:Tensile Strength / Q000187:drug effects; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology
D004338:Drug Combinations; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide