title: Effect of different polymerization methods on composite microleakage.
abstract: OBJECTIVE
  To evaluate the microleakage of a condensable resin composite using a microhybrid flowable composite as a liner, cured with four different methods of polymerization.
  
  
  METHODS
  40 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into four groups. Group 1 (control group): conventional mode (Elipar Highlight), Group 2: step mode (Elipar Highlight), Group 3: ramp mode (Elipar Trilight) and Group 4: pulse mode (VIP). Preparations were etched with 32% phosphoric acid (Uni-Etch) and an adhesive system (One-Step) was used according to the manufacturer's instructions. Teeth were then restored using a 1 mm layer of flowable composite (A2 AEliteflo LV) on the gingival and pulpal floor and condensable composite (Pyramid A2 Dentin and A1 Enamel) in 2 mm increments. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x30 magnification. Dye penetration was scored using an ordinal scoring system as 0: no penetration; 1: enamel penetration; 2: dentin penetration.
  
  
  RESULTS
  A Mann-Whitney U Test revealed a statistically significant difference between Group 1 with Groups 2, 3 and 4 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between Groups 2, 3 and 4.
authors.affiliation: Department of Conservative Dentistry, University of Cagliari, Italy. simone.deliperi@tufts.edu
authors.forename: Simone
authors.initials: S
authors.lastname: Deliperi
authors.forename: David N
authors.initials: DN
authors.lastname: Bardwell
authors.forename: Aikaterini
authors.initials: A
authors.lastname: Papathanasiou
mesh_terms: D000134:Acid Etching, Dental; D017609:Barium Compounds / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003736:Dental Cavity Lining; D003737:Dental Cavity Preparation / Q000379:methods; D003763:Dental Leakage / Q000145:classification*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008751:Methylene Blue; D010756:Phosphoric Acids / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D018709:Statistics, Nonparametric; D013499:Surface Properties
chemical_list: C121035:Aeliteflo; D017609:Barium Compounds; C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; D004396:Coloring Agents; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D010756:Phosphoric Acids; D011108:Polymers; C428803:Pyramid Packable Composite; D019279:Resin Cements; C111840:flowable hybrid composite; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D008751:Methylene Blue