Abstract: Introduction: Evaluation of microleakage is important for assessing the
success of new restorative materials and methods. The aim of this study was to assess the
microleakage of class II restorations with different flowable composites as liners and two
different polymerization techniques classic and soft start.
Materials and Methods: 40 extracted human premolars teeth with class II cavity
preparation medial and distal (80 cavities) were divided into four groups: 1.Vertise Flow
(VF)+micro hybrid composite Herculite 2.Surefil SDR Flow (SDRF)+micro-hybrid
composite Herculite 3.Tetric Flow (TF)+micro-hybrid composite Herculite 4.control group
micro-hybrid composite Herculite. Mesial cavities are polymerized with classic and distal
cavity with soft start technique of polymerization. After that, the samples were immersed in
0.5% AgNO3 solution and sectioned into the mesiodistal direction. Using a stereomicroscope
(Nikon – Japan), with a magnification of 40x, the gingival microleakage of cavities was
examined. Data were analyzed using Fisher’s and Student’s tests.
Results: After using the classical polymerization technique, all three used flowable
composites VF+Herculite, SDRF+Herculite, TF+Herculite showed less gingival
microleakage than the control group. This difference was statistically significant. After the
application of the soft-start technique of polymerization, VF+Herculite and SDRF+Hercules
showed a statistically significant reduction in gingival microleakage, while TF+Herculite
showed a comparable result with control group, without a statistically significant difference.
There was no statistically significant difference between classical and soft start
polymerization techniques.
Conclusion: Flowable composites in this study have reduced gingival microleakage
and can be used as liners in the restoration of II class cavities.