title: Effect of light curing methods on microleakage and microhardness of different resin sealants.
abstract: OBJECTIVE
  This study's purpose was to evaluate the effect of light curing methods on the microleakage and microhardness of sealants.
  
  
  METHODS
  The Elipar Free Light 2 light emitting diode (LED) with 10- and 20-second curing times, and the Elipar 2500 halogen light with  a 20-second curing time were compared. Four different sealants were used: (1) Delton Clear; (2) Delton Opaque; (3) UltraSeal XT Clear; and (4) UltraSeal XT Opaque. Specimens were fabricated in a silicone mold (2-mm thick) and cured. Knoop hardness was measured at the bottom and top surfaces.  For the microleakage evaluation, 120 human molars were divided into 12 groups and sealed with the sealants and curing methods, as stated previously. The teeth were thermocycled and immersed in 2% methylene blue for 24 hours. Each tooth was sectioned and examined for dye penetration.
  
  
  RESULTS
  There were no statistically significant differences in the microleakage of sealants polymerized by either the halogen or LED curing methods. The microhardness of sealants varied according to the type of material and curing method.
  
  
  CONCLUSIONS
  A 10-second polymerization time with  light emitting diodes was not sufficient to cure the 2-mm-thick opaque or high filler loaded sealants. Decreasing the curing time, however, had no effect on the microleakage of the sealants.
authors: Faculty of Dentistry, Thammasat University, Pathumthani, Thailand. dduangporn@yahoo.com
authors: Duangporn
authors: D
authors: Duangthip
authors: Suda
authors: S
authors: Ballungpattama
authors: Thanya
authors: T
authors: Sitthisettapong
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry* / Q000528:radiation effects*; D003188:Composite Resins; D003763:Dental Leakage / Q000145:classification* / Q000517:prevention & control; D003793:Dental Restoration, Permanent / Q000295:instrumentation; D006219:Halogens; D006244:Hardness; D008027:Light; D016014:Linear Models; D008422:Materials Testing; D044367:Phase Transition; D010895:Pit and Fissure Sealants / Q000737:chemistry* / Q000528:radiation effects*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; D006219:Halogens; D010895:Pit and Fissure Sealants; C106663:Ultra Seal XT; D017438:Bisphenol A-Glycidyl Methacrylate