title: Effect of mechanical load cycling on the marginal integrity of adhesive Class I resin composite restorations.
abstract: OBJECTIVE
  The purpose of this study was to determine the effect of cycle loading on the sealing capacity of different adhesive systems in Class I restorations in vitro.
  
  
  METHODS
  (1) Clearfil Liner Bond/Clearfil Photo Posterior, (2) Scotchbond Multipurpose/Z100, (3) Syntae/Heliomolar, and (4) Gluma 2000/Pekalux were employed to restore Class I cavities in extracted human premolars and molars. For each test group, half of the specimens were subjected to mechanical loading at 125 N for 5000 cycles in a dye solution. After sectioning, dye penetration was assessed.
  
  
  RESULTS
  Without loading, no specimen showed leakage, while loading did affect the sealing capacity of groups 3 and 4. Groups 1 and 2 showed no significant increase in leakage after the loading procedure.
  
  
  CONCLUSIONS
  The results indicate that mechanical cycle loading can adversely affect the interface of adhesive Class I resin composite restorations unless hybridizing adhesive systems are used.
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, University of Tanta, Egypt.
authors.forename: A I
authors.initials: AI
authors.lastname: Abdalla
authors.forename: C L
authors.initials: CL
authors.lastname: Davidson
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000269:Adhesives / Q000737:chemistry*; D001641:Bicuspid; D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003763:Dental Leakage / Q000175:diagnosis; D003793:Dental Restoration, Permanent / Q000145:classification*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D006801:Humans; D008689:Methacrylates / Q000737:chemistry; D008963:Molar; D010070:Oxalates / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D000269:Adhesives; C084544:Clearfil Linerbond System; D004396:Coloring Agents; C029012:Composite Dental Resin; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C092418:Gluma 2000; C513708:Heliomolar; D008689:Methacrylates; D010070:Oxalates; D011140:Polyurethanes; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C078484:Syntac dentine adhesive; C083568:Z100 composite resin; C092420:Clearfil Photo Posterior; C076985:Pekalux; D012822:Silicon Dioxide; D015040:Zirconium; D005998:Glycine