title: The effect of curing light variations on bulk curing and wall-to-wall quality of two types and various shades of resin composites.
abstract: OBJECTIVE
  This study evaluated the influence of light intensity and irradiation time variations on the curing efficacy of two types and various shades of resin composites and the effect of reduced light intensity on the preservation of wall-to-wall continuity.
  
  
  METHODS
  Three microfilled composites (in three different shades) and one hybrid composite were used in this study. Polymerization shrinkage, and the hardness and adaptation of adhesive restorations in dentin cavities were determined at light intensities of 175 and 700 mW/cm2 and irradiation times of 10 and 60 s. Data were compared using in a general linear model analysis.
  
  
  RESULTS
  Shrinkage measurements were the indication of conversion and conversion rate. Reduced intensity slowed down the rate of polymerization but did not reduce the conversion as long as an irradiation time of 60 s was employed. High-energy irradiation caused increased separation of the composite from the tooth structure. On the basis of obtaining optimal conversion and adaption, it was demonstrated that the irradiation time to be more effective than irradiation energy.
  
  
  CONCLUSIONS
  Light-cured composites require an understanding of their structure, pigmentation and irradiation parameters to obtain optimal performance. High intensity light-curing does not necessarily lead to optimal quality.
authors.affiliation: Department of Restorative Dentistry and Endodontics, School of Dentistry, University of Ege, Izmir, Turkey. c.davidson@acta.nl
authors.forename: S S
authors.initials: SS
authors.lastname: Davidson-Kaban
authors.forename: C L
authors.initials: CL
authors.lastname: Davidson
authors.forename: A J
authors.initials: AJ
authors.lastname: Feilzer
authors.forename: A J
authors.initials: AJ
authors.lastname: de Gee
authors.forename: N
authors.initials: N
authors.lastname: Erdilek
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000295:instrumentation; D005069:Evaluation Studies as Topic; D006244:Hardness; D008027:Light; D011108:Polymers / Q000737:chemistry; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003432:Cross-Linking Reagents; D011108:Polymers; C065771:P50 composite resin; C074741:Silux Plus; D017438:Bisphenol A-Glycidyl Methacrylate