title: Comparative evaluation of marginal adaptation between nanocomposites and microhybrid composites exposed to two light cure units.
abstract: BACKGROUND
  Recent advances in resin adhesives and restorative materials, as well as an increased demand for esthetics, have lead to the introduction of newer resin-based composites like nanocomposites and light-curing units like light emitting diodes (LEDs).
  
  
  OBJECTIVE
  The present study was conducted to evaluate the effect of conventional quartz tungsten halogen (QTH) curing unit and blue LED on marginal adaptation of microhybrid composite (Filtek Z250) and nanocomposite (Filtek Z350) resins.
  
  
  METHODS
  Eighty Class V cavities were prepared on, extracted human premolars and were divided into four groups of 20 each. The four groups were designed according to the restorative resin and light cure unit used microhybrid/QTH, nanocomposites/QTH, microhybrid/LED and nanocomposites/LED. After thermocycling and immersion in 2% Basic Fuschin dye solution, the teeth were sectioned and dye penetration was observed under a stereomicroscope at 20X magnification.
  
  
  METHODS
  All the samples were scored and results were analyzed using the "Kruskal Wallis and Mann Whitney tests" with "Wilcoxone correction."
  
  
  RESULTS
  The results revealed least microleakage in microhybrid composites exposed to QTH and maximum in nanocomposites exposed to LED.
  
  
  CONCLUSIONS
  Microhybrid composites exhibited lesser microleakage than nanocomposite resins.
authors: Department of Conservative Dentistry and Endodontics, Himachal Institute of Dental Sciences, Poanta Sahib, Himachal Pradesh, India. dr.ruchidhir@yahoo.co.in
authors: Ruchi Dhir
authors: RD
authors: Sharma
authors: Jaideep
authors: J
authors: Sharma
authors: Anuradha
authors: A
authors: Rani
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D003763:Dental Leakage / Q000517:prevention & control; D018772:Dental Marginal Adaptation / Q000592:standards*; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation* / Q000379:methods; D053761:Nanocomposites / Q000737:chemistry
chemical_list: D003188:Composite Resins; C444701:Filtek Z250; C533204:filtek Z350