title: Nd:YAG laser effects on the microleakage of composite resin restorations.
abstract: OBJECTIVE
  This study evaluated microleakage of composite restorations submitted to marginal treatment with Nd:YAG laser and surface sealant.
  
  
  BACKGROUND
  Previous studies have demonstrated that Nd:YAG-lased enamel melted and became recrystallized with a morphologic appearance similar to lava, and has been used clinically in the sealing of enamel pits and fissures.
  
  
  METHODS
  Class V cavities in enamel of human premolars were restored with composite resin (Z100, 3M) and randomly divided in six groups: G1, control; G2, surface sealant marginal treatment; G3 to G6, were treated with pulsed Nd:YAG laser (1.064 microm) marginal treatment, contact fiberoptic (300 microm), air cooling, for 30 seconds, powers of 1.2-2 W, repetition rates of 20-30 Hz, energies of 40-100 mJ. Teeth were impermeabilized, immersed in a rhodamine dye, sectioned, and evaluated under stereomicroscope microscopy with scores.
  
  
  RESULTS
  There were significant differences between marginal treatments; there were no differences between groups 1, 2, and 4, and 3,5, and 6; lower values of microleakage were at groups 3, 5, and 6 (Kruskal-Wallis,p = 0.05).
  
  
  CONCLUSIONS
  Nd:YAG laser showed improved marginal sealing and decreased microleakage of composite resins restorations.
authors.affiliation: Department of Restorative Dentistry-School of Dentistry University of São Paulo, SP, Brazil. rnavarro@fo.usp.br
authors.forename: R S
authors.initials: RS
authors.lastname: Navarro
authors.forename: G V
authors.initials: GV
authors.lastname: Esteves
authors.forename: W T
authors.initials: WT
authors.lastname: Oliveira
authors.forename: A B
authors.initials: AB
authors.lastname: Matos
authors.forename: C P
authors.initials: CP
authors.lastname: Eduardo
authors.forename: M N
authors.initials: MN
authors.lastname: Youssef
authors.forename: E
authors.initials: E
authors.lastname: Matson
mesh_terms: D000180:Acrylic Resins / Q000528:radiation effects*; D003188:Composite Resins / Q000528:radiation effects*; D003731:Dental Caries / Q000532:radiotherapy*; D003743:Dental Enamel / Q000528:radiation effects; D003763:Dental Leakage / Q000532:radiotherapy*; D003793:Dental Restoration, Permanent; D006801:Humans; D066298:In Vitro Techniques; D011140:Polyurethanes / Q000528:radiation effects*
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes