title: CO2 laser and/or fluoride enamel treatment against in situ/ex vivo erosive challenge.
abstract: OBJECTIVE
  This in situ/ex vivo study investigated the effect of CO2 laser irradiation and acidulated phosphate fluoride gel (APF) application, separately and in combination, on enamel resistance to erosion.
  
  
  METHODS
  During 2 experimental 5-day crossover phases, 8 volunteers wore intraoral appliances containing bovine enamel blocks which were submitted to four groups: 1st phase - control, untreated and CO2 laser irradiation, 2nd phase - fluoride application and fluoride application before CO2 laser irradiation. Laser irradiation was performed at 10.6 µm wavelength, 5 µs pulse duration and 50 Hz frequency, with average power input and output of 2.3 W and 2.0 W, respectively (28.6 J/cm2). APF gel (1.23%F, pH 3.5) was applied on enamel surface with a microbrush and left on for 4 minutes. Then, the enamel blocks were fixed at the intraoral appliance level. The erosion was performed extraorally 4 times daily for 5 min in 150 mL of cola drink. Enamel loss was measured profilometrically after treatment and after the in situ phase. The data were tested using one-way Repeated Measures Anova and Tukey's test (p<0.05).
  
  
  RESULTS
  CO2 laser alone (2.00±0.39 µm) did not show any significantly preventive effect against enamel erosion when compared with the control group (2.41±1.20 µm). Fluoride treated enamel, associated (1.50±0.30 µm) or not (1.47±0.63 µm) with laser irradiation, significantly differed from the control.
  
  
  CONCLUSIONS
  The APF application decreased enamel wear; however, CO2 laser irradiation did not enhance fluoride ability to reduce enamel wear.
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Maísa Camillo
authors.initials: MC
authors.lastname: Jordão
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Gustavo Manzano
authors.initials: GM
authors.lastname: Forti
authors.affiliation: - Universidade Camilo Castelo Branco, Departamento de Odontopediatria, São Paulo, SP, Brasil.
authors.forename: Ricardo Scarparo
authors.initials: RS
authors.lastname: Navarro
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia, Laboratório Especial de Laser em Odontologia, São Paulo, SP, Brasil.
authors.forename: Patrícia Moreira
authors.initials: PM
authors.lastname: Freitas
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Heitor Marques
authors.initials: HM
authors.lastname: Honório
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Daniela
authors.initials: D
authors.lastname: Rios
mesh_terms: D000149:Acidulated Phosphate Fluoride / Q000627:therapeutic use*; D000328:Adult; D000818:Animals; D002327:Cariostatic Agents / Q000627:therapeutic use; D002417:Cattle; D003131:Combined Modality Therapy; D003743:Dental Enamel / Q000187:drug effects* / Q000528:radiation effects*; D004311:Double-Blind Method; D005260:Female; D005782:Gels; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use*; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors; D014077:Tooth Erosion / Q000517:prevention & control*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D002327:Cariostatic Agents; D005782:Gels; D000149:Acidulated Phosphate Fluoride