title: Effect of Thermo-mechanical Load Cycling on Microleakage in Class II Ormocer Restorations.
abstract: OBJECTIVE
  The objective of this in vitro study was to evaluate the marginal sealing ability of an ormocer in comparison with a hybrid composite when using thermocycling and load cycling procedures together in the study design.
  
  
  METHODS
  Modified proximal Class II cavities were prepared on the mesial and distal surfaces of twenty-two human premolars. Each tooth was restored with Admira and contralaterally with TPH Spectrum. Half of all of the teeth were subjected to thermo-mechanical load cycling. After dye penetration, longitudinal sections in mesio-distal direction were prepared and examined under a stereomicroscope. Data were analyzed with Mann Whitney U test.
  
  
  RESULTS
  The results showed that the thermo-mechanical load cycling caused a statistically significant increase in gingival microleakage when compared with the non-thermocycled and non-loaded restorations for both the materials Admira (P=0.006) and TPH Spectrum (P=0.023).
  
  
  CONCLUSIONS
  Simultaneous load cycling and thermocycling are decisive factors in the in vitro assessment of gingival microleakage, which still remains to be a clinical problem even with the ormocer system Admira.
authors.affiliation: Dr, Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, Istanbul, Turkey.
authors.forename: Dina
authors.initials: D
authors.lastname: Erdilek
authors.forename: Can
authors.initials: C
authors.lastname: Dörter
authors.forename: Fatma
authors.initials: F
authors.lastname: Koray
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kunzelmann
authors.forename: Begum Guray
authors.initials: BG
authors.lastname: Efes
authors.forename: Yavuz
authors.initials: Y
authors.lastname: Gomec