title: Spectrophotometric and colorimetric evaluation of staining of the light cured composite after exposure with different intensities of light curing units.
abstract: OBJECTIVE
  To understand the importance of intensity of light in polymerizing light cured composites and its relation to color stability.
  
  
  METHODS
  Forty specimens of composite disc with 3mm diameter and 1.5 mm thick were divided into two groups of 20 samples each. Group1: Twenty samples were cured with a light curing unit of380mw/cm(2). Group2: Twenty samples cured with a light curing unit of 680mw/cm(2). These polymerized samples were immersed in methylene blue dye for 24hoursand later washed and immersed in absolute alcohol for 24 hours. The amount of color released into absolute alcohol was assessed by spectrophotometric and colorimetric analysis.
  
  
  RESULTS
  Results were analyzed for spectrophotometric and colorimetric values by using the Mann-Whitney test. The group cured with low intensity light stained more compared to the group cured with a normal intensity of light.
  
  
  CONCLUSIONS
  Intensity of light plays a crucial role in staining of the polymerized light cured composite. The intensity of the curing unit has to be maintained in acceptable limits to achieve good clinical results.
authors.affiliation: Department of conservative Dentistry and Endodontics, Mamata Dental College, Khammam, Andhra Pradesh, India.
authors.forename: Veeramachaneni
authors.initials: V
authors.lastname: Chandrasekhar
authors.forename: L Pramod
authors.initials: LP
authors.lastname: Reddy
authors.forename: T Jaya
authors.initials: TJ
authors.lastname: Prakash
authors.forename: G Anitha
authors.initials: GA
authors.lastname: Rao
authors.forename: M
authors.initials: M
authors.lastname: Pradeep