title: Carbamide peroxide bleaching agents: effects on surface roughness of enamel, composite and porcelain.
abstract: This study examined the effect of 10 and 35% carbamide peroxide bleaching agents on the surface roughness of enamel, feldspathic porcelain, and microfilled and microhybrid composite resins. Standardized cylindrical specimens were prepared for restorative materials. Enamel samples were obtained from buccal and lingual surfaces of human molars. Samples from each substrate were divided in three subgroups (n=10), according to surface treatment: distilled water (control), and 10 and 35% carbamide peroxide. The 10% agent was applied 3 h daily and the 35% agent was applied for 30 min/week, at 37 degrees C, during 21 days. Control samples remained stored in distilled water, at 37 degrees C. Roughness measurements (Ra, microm) were made at 24 h and repeated after 7, 14 and 21 days of exposure. Data were analyzed using ANOVA (split-plot design) and Tukey's test (5% significance level). Samples from control groups showed no significant alteration during all test periods, while for exposure to 10% agent, only the porcelain presented a rougher surface after 21 days (p<0.05). For the 35% product, roughness means significantly increased during the first and second weeks for enamel (p<0.05), and after 21 days for porcelain (p<0.05) and for the microhybrid composite (p<0.05). Microfilled samples showed no significant alteration throughout the 21-day period, regardless of the surface treatment.
authors.affiliation: Department of Restorative Dentistry, Dental Materials Area, Piracicaba School of Dentistry, State University of Campinas, 901, Limeira Av., 13414-903 Areião, Piracicaba SP, Brazil.
authors.forename: R R
authors.initials: RR
authors.lastname: Moraes
authors.forename: J L M
authors.initials: JL
authors.lastname: Marimon
authors.forename: L F J
authors.initials: LF
authors.lastname: Schneider
authors.forename: L
authors.initials: L
authors.lastname: Correr Sobrinho
authors.forename: G B
authors.initials: GB
authors.lastname: Camacho
authors.forename: M
authors.initials: M
authors.lastname: Bueno
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D000077463:Carbamide Peroxide; D003188:Composite Resins / Q000737:chemistry*; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D004338:Drug Combinations; D006801:Humans; D008422:Materials Testing; D016877:Oxidants / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D010545:Peroxides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D017680:Potassium Compounds / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014073:Tooth Bleaching; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D014867:Water / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; D003764:Dental Materials; D004338:Drug Combinations; C095718:Duceram; C452225:Filtek A110 composite resin; C444701:Filtek Z250; D016877:Oxidants; D010545:Peroxides; D017680:Potassium Compounds; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; D000077463:Carbamide Peroxide; D014508:Urea