title: Role of delayed light polymerization of a dual-cured composite base on marginal adaptation of class II posterior composite open-sandwich restoration.
abstract: OBJECTIVE
  To determine the effect of delayed light polymerization of a dual-cured composite base material on the marginal adaptation of class II composite restoration.
  
  
  METHODS
  35 extracted human molar teeth were used to prepare class II mesio-occlusal or disto-occlusal slot preparations with gingival margins at the CEJ. The teeth were restored using an open-sandwich technique with a 2mm base increment of dual-cured composite, and divided into 5 groups based on the mode of the polymerization of the dual-cured composite base: Group A - self-cured after placement (5 mins), Group B - light-cured immediately after placement, Group C - light-cured 30 seconds after placement, Group D - light-cured 60 seconds after placement, Group E - light-cured 120 seconds after placement. Then a top layer of a light-cured composite resin is placed to complete the restoration. The teeth were thermocycled and immersed in 1% aqueous solution of methylene blue for 24 hours. Sectioning of the teeth and scoring under stereomicroscope was done. Data will be statistically evaluated using the kruskal wallis 1-way ANOVA.
  
  
  RESULTS
  Statistical analysis using kruskal wallis 1-way ANOVA showed that the dual-cured composite light polymerized 1 minute after placement exhibited the least microleakage.
  
  
  CONCLUSIONS
  Delayed light polymerization of the dual-cured composite base reduced the microleakage in class II open-sandwich restorations.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Dr. Syamala Reddy Dental College, Banglore, India.
authors.forename: Uday
authors.initials: U
authors.lastname: Kamath
authors.forename: Hina
authors.initials: H
authors.lastname: Sheth
mesh_terms: D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D001840:Dental Bonding / Q000379:methods; D003737:Dental Cavity Preparation / Q000145:classification; D003763:Dental Leakage / Q000145:classification; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects*; D003793:Dental Restoration, Permanent / Q000145:classification* / Q000379:methods; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D006813:Humidity; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D008422:Materials Testing; D008751:Methylene Blue; D058105:Polymerization; D055116:Self-Curing of Dental Resins / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D019237:Tooth Cervix / Q000473:pathology
chemical_list: D004396:Coloring Agents; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C529053:rebilda DC; C100748:Polofil Molar; D008751:Methylene Blue