title: Effect of light-curing units in shear bond strength of metallic brackets: an in vitro study.
abstract: OBJECTIVE
  To determine the influence of the light curing units on the shear bond strength of orthodontic brackets.
  
  
  METHODS
  Seventy-two premolars were divided into six groups (n=12): Group I: brackets bonded with Transbond and polymerization with halogen light; Group II: Transbond and LED; Group III: Fuji Ortho and halogen light; Group IV: Fuji Ortho and LED; Group V: Fuji Ortho, without acid and halogen light; Group VI: Fuji Ortho, without acid and LED. The groups were tested to shear strength in a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test.
  
  
  RESULTS
  The composite resin presented higher shear bond strength than the resin-modified glass ionomer cement (p<0.05). The halogen light and LED sources produced similar shear bond strength (p>0.05).
  
  
  CONCLUSIONS
  The shear bond strength was influenced by the material but not by the light-curing unit. The use of LED reduced the experimental time by approximately 60%, with the same curing efficiency.
authors.affiliation: Pontifical Catholic University of Rio Grande do Sul, Curitiba, PR, Brazil. retamosolb@gmail.com
authors.forename: Luciana Borges
authors.initials: LB
authors.lastname: Retamoso
authors.forename: Niége Michelle Lazzari
authors.initials: NM
authors.lastname: Onofre
authors.forename: Luciane
authors.initials: L
authors.lastname: Hann
authors.forename: Ernani Menezes
authors.initials: EM
authors.lastname: Marchioro
mesh_terms: D000134:Acid Etching, Dental; D000180:Acrylic Resins / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D055117:Curing Lights, Dental / Q000145:classification; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D016910:Orthodontic Brackets; D011108:Polymers / Q000737:chemistry; D011829:Radiation Dosage; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D000538:Aluminum Silicates; D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; C112133:Fuji Ortho; D005899:Glass Ionomer Cements; D011108:Polymers; D019279:Resin Cements; C477790:Transbond XT; D013193:Stainless Steel