title: Microleakage of four simplified adhesive systems under thermal and mechanical stresses.
abstract: OBJECTIVE
  To evaluate microleakage at the dentin margins of Class II resin-based composite restorations using four simplified adhesive systems: Etch & Prime 3.0, Prime & Bond NT, Clearfil Liner Bond 2V and Clearfil SE Bond, upon thermal and mechanical stresses.
  
  
  METHODS
  Forty slot preparations (5mm x 3mm x 1.5mm) were cut in sound human molars with gingival margins below the cement/enamel junction. All adhesive systems were applied strictly according to manufacturers' instructions. Cavities were restored using Clearfil AP-X composite resin. After finishing and polishing, teeth were submitted to thermal (x700, 5-55 degrees C, 60-second dwell time) and consecutively mechanical cycling (100,000 cycle; 8 Kgf load). Specimens were coated with nail polish, immersed in silver nitrate for 2 hours and sectioned longitudinally with a diamond disc. The extent of leakage was ranked using a 0-4 scale.
  
  
  RESULTS
  Statistical analysis was performed using Kruskal-Wallis test. Minimal leakage occurred with Clearfil SE Bond. There was a statistically significant difference (P<0.01) between this system and Clearfil Liner Bond 2V, although the latter also showed low values of dye penetration. No statistically significant difference was found between Etch & Prime 3.0 and Prime & Bond NT. Both showed statistically greater leakage than the two other systems (P<0.01).
authors.affiliation: Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, Brazil. paulocapel@uol.com.br
authors.forename: Paulo Eduardo Capel
authors.initials: PE
authors.lastname: Cardoso
authors.forename: Eliane
authors.initials: E
authors.lastname: Placido
authors.forename: Sandra Kiss
authors.initials: SK
authors.lastname: Moura
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003763:Dental Leakage / Q000145:classification*; D003775:Dental Polishing; D003793:Dental Restoration, Permanent / Q000145:classification; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D008689:Methacrylates / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D016622:Silver Staining; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013816:Thermodynamics; D019237:Tooth Cervix / Q000648:ultrastructure
chemical_list: C112828:Clearfil AP-X; C112274:Clearfil Liner Bond 2; C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C469823:Etch&Prime 3.0; D008689:Methacrylates; D010710:Phosphates; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; D000431:Ethanol