title: The effect of thermocycling on microleakage of several commercially available composite Class V restorations in vitro.
abstract: BACKGROUND
  Microleakage is a major factor contributing to the occurrence of secondary carious lesions around composite restorations.
  
  
  OBJECTIVE
  This in vitro study investigated the effect of thermocycling on microleakage of several composite Class V restorations.
  
  
  METHODS
  One hundred twenty molars were randomly distributed into 6 groups of 20 teeth. Class V preparations were made in the buccal and lingual surfaces of each tooth and restored in bulk by use of 6 composites (Arabesk, Silux-Plus, Solitaire 2, Durafill VS, Charisma, and Renew) according to the manufacturers' recommendations. The teeth were stored in distilled water at room temperature for 24 hours. The teeth in each group were divided randomly into 2 subgroups: (a) thermocycled for 500 cycles between 5 degrees and 55 degrees C with a dwell time of 30 seconds, (b) no thermocycling treatment. All restored teeth were immersed in 1% methylene blue dye for 4 hours and sectioned buccolingually with a diamond wheel. Dye penetration was scored by use of a stereomicroscope at original magnification x4. The generalized linear models statistical analysis was used (alpha=.05).
  
  
  RESULTS
  The preparation margins (enamel/dentin) and thermocycling had a significant effect on microleakage (P=.0351, P<.0001, respectively); the type of material had no significant effect (P=.1689).
  
  
  CONCLUSIONS
  Thermocycling significantly increased the microleakage (P<.0001). The overall microleakage at the enamel margins was significantly less than at the dentinal margins (P=.0351).
authors.affiliation: University of Jordan, Amman. fouadk@ju.edu.jo
authors.forename: Fouad K
authors.initials: FK
authors.lastname: Wahab
authors.forename: Firas J
authors.initials: FJ
authors.lastname: Shaini
authors.forename: Steven M
authors.initials: SM
authors.lastname: Morgano
mesh_terms: D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry*; D003737:Dental Cavity Preparation / Q000145:classification; D003743:Dental Enamel / Q000648:ultrastructure; D003763:Dental Leakage / Q000145:classification* / Q000473:pathology; D003793:Dental Restoration, Permanent / Q000145:classification*; D003804:Dentin / Q000648:ultrastructure; D006801:Humans; D016014:Linear Models; D008422:Materials Testing; D008751:Methylene Blue; D008963:Molar; D013816:Thermodynamics; D013997:Time Factors
chemical_list: C425826:Arabesk; C084111:Charisma composite resin; D004396:Coloring Agents; D003188:Composite Resins; C469658:Solitaire 2 composite resin; C074741:Silux Plus; C039734:Durafill; D008751:Methylene Blue