title: Effect of enamel preparation method on in vitro marginal microleakage of a flowable composite used as pit and fissure sealant.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate the microleakage in occlusal surfaces, after preparation with Er:YAG laser and compared to the diamond-bur conventional technique.
  
  
  METHODS
  Thirty premolars were divided into three groups: I - high-speed handpiece + 37% phosphoric acid; II - Er:YAG laser (350 mJ, 4 Hz and 112 J/cm(2)) + 37% phosphoric acid; and III - Er:YAG laser (350 mJ, 4 Hz and 112 J/cm(2)) + Er:YAG laser (80 mJ, 4 Hz, and 25 mJ/cm(2)). All cavities received the same adhesive system and were restored with flowable composite according to manufacturer's instructions. Teeth were submitted to thermal cycling and immersed in 50% silver nitrate solutions for 8 h in total darkness. Specimens were sectioned longitudinally in the bucco-lingual direction, in slices of 1 mm thick. Each slice was immersed into photo developing solution and was photographed, and microleakage was scored from 0 to 7, by three calibrated examiners.
  
  
  RESULTS
  A statistically significant difference (P < 0.0001) was observed between Er:YAG laser prepared and etched specimens and those in the other groups.
  
  
  CONCLUSIONS
  It can be concluded that no significant difference was noted between the two types of enamel preparation when etching was performed. Preparing and treating the enamel surface exclusively by Er:YAG laser resulted in the highest degree of leakage.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, University of São Paulo, Brazil. michel@usp.br
authors.forename: M N
authors.initials: MN
authors.lastname: Youssef
authors.forename: F A
authors.initials: FA
authors.lastname: Youssef
authors.forename: W C
authors.initials: WC
authors.lastname: Souza-Zaroni
authors.forename: M L
authors.initials: ML
authors.lastname: Turbino
authors.forename: M M F
authors.initials: MM
authors.lastname: Vieira
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D016009:Chi-Square Distribution; D003188:Composite Resins / Q000737:chemistry; D003763:Dental Leakage; D006801:Humans; D053685:Laser Therapy; D010895:Pit and Fissure Sealants / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D018709:Statistics, Nonparametric; D019246:Tooth Preparation / Q000295:instrumentation / Q000379:methods*
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D010895:Pit and Fissure Sealants; D011140:Polyurethanes