title: Influence of ultrasound or halogen light on microleakage and hardness of enamel adjacent to glass ionomer cement.
abstract: BACKGROUND
  The use of external sources of energy may accelerate the setting rate of glass ionomer cements (GICs) allowing better initial mechanical properties.
  
  
  OBJECTIVE
  To investigate the influence of ultrasound and halogen light on the microleakage and hardness of enamel adjacent to GIC restorations, after artificial caries challenge.
  
  
  METHODS
  Cavities were prepared in 60 primary canines, restored with GIC, and randomly distributed into three groups: control group (CG), light group (LG) - irradiation with a halogen light-curing unit for 60s, and ultrasonic group (UG) - application of ultrasonic scaler device for 15s. All specimens were then submitted to a cariogenic challenge in a pH cycling model. Half of sample in each group were immersed in methylene blue for 4h and sectioned for dye penetration analysis. The remaining specimens were submitted to Knoop cross-sectional microhardness assessments, and mineral changes were calculated for adjacent enamel.
  
  
  RESULTS
  Data were compared using Kruskal-Wallis test and two-way ANOVA with 5% significance. Higher dye penetration was observed for the UG (P<0.01). No significant mineral changes were observed between groups (P=0.844).
  
  
  CONCLUSIONS
  The use of halogen light-curing unit does not seem to interfere with the properties of GICs, whereas the use of ultrasound can affect its marginal sealing.
authors.affiliation: Department of Orthodontics and Pediatric Dentistry, Faculdade de Odontologia da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Camila Almeida Brandão
authors.initials: CA
authors.lastname: Guglielmi
authors.forename: Anice
authors.initials: A
authors.lastname: Mohana
authors.forename: Daniela
authors.initials: D
authors.lastname: Hesse
authors.forename: Tathiane Larissa
authors.initials: TL
authors.lastname: Lenzi
authors.forename: Gabriela Cunha
authors.initials: GC
authors.lastname: Bonini
authors.forename: Daniela Prócida
authors.initials: DP
authors.lastname: Raggio
mesh_terms: D000704:Analysis of Variance; D055117:Curing Lights, Dental / Q000145:classification; D003731:Dental Caries / Q000628:therapy*; D003743:Dental Enamel / Q000187:drug effects* / Q000528:radiation effects; D003763:Dental Leakage / Q000517:prevention & control*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods; D005899:Glass Ionomer Cements / Q000528:radiation effects / Q000627:therapeutic use*; D006244:Hardness; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D014465:Ultrasonics
chemical_list: D005899:Glass Ionomer Cements