title: Ultrastructural evaluation of enamel after dental bleaching associated with fluoride.
abstract: This study evaluated the effects on human enamel after two bleaching procedures: with a fluoridated bleaching agent and with topical fluoride application postbleaching. It used 43 enamel blocks (3 mm(2) ) that were ground flat (600-2,000 grit) and polished with polishing paste (one and one-fourth). Specimens were randomly divided into three groups according to the bleaching procedure: (1) control group, (2) hydrogen peroxide 35% (HPF) and topical application of fluoride 1.23%, and (3) HP 38% (OP) with fluoride in its composition. Bleaching agents were used according to the manufacturer's instructions. Three methodologies were used: nanoindentation, to observe surface hardness and elastic modulus; atomic force microscopy, to observe surface roughness (R(a) - R(z)); and scanning electron microscopy, to observe the enamel surface effects. Group OP had a decrease in the elastic modulus after bleaching, which was recovered at 14 days. An increased roughness (R(a); 32%) was observed on group HPF and had an increased erosion on enamel surface (67%). It was concluded that topical application of fluoride, after using the nonfluoridated whitening agent, increased the roughness values and erosion of enamel.
authors.affiliation: Pós-graduação em Odontologia, Universidade Estadual de Ponta Grossa, Ponta Grossa, Paraná, Brazil. johnalexis.dominguez@gmail.com
authors.forename: John A
authors.initials: JA
authors.lastname: Dominguez
authors.forename: Bruna
authors.initials: B
authors.lastname: Bittencourt
authors.forename: Milton
authors.initials: M
authors.lastname: Michel
authors.forename: Nilson
authors.initials: N
authors.lastname: Sabino
authors.forename: João Carlos
authors.initials: JC
authors.lastname: Gomes
authors.forename: Osnara M M
authors.initials: OM
authors.lastname: Gomes
mesh_terms: D003743:Dental Enamel / Q000187:drug effects / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000379:methods*; D055119:Elastic Modulus; D005460:Fluorides, Topical / Q000008:administration & dosage* / Q000494:pharmacology; D006244:Hardness; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D011897:Random Allocation; D012464:Saliva, Artificial / Q000008:administration & dosage / Q000494:pharmacology; D013499:Surface Properties; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000008:administration & dosage / Q000494:pharmacology*; D014077:Tooth Erosion / Q000139:chemically induced / Q000473:pathology
chemical_list: D005460:Fluorides, Topical; D012464:Saliva, Artificial; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide