Local deformation fields and marginal integrity of sculptable bulk-fill, low-shrinkage and conventional composites.
To compare strain and displacement of sculptable bulk-fill, low-shrinkage and conventional composites as well as dye penetration along the dentin-restoration interface.



Modified Class II cavities (N=5/group) were filled with sculptable bulk-fill (Filtek Bulk Fill Posterior, 3M ESPE; Tetric EvoCeram Bulk Fill, Ivoclar Vivadent; fiber-reinforced EverX Posterior, GC; giomer Beautifil Bulk, Schofu), low-shrinkage (Kalore, GC), nanohybrid (Tetric EvoCeram, Ivoclar Vivadent) or microhybrid (Filtek Z250, 3M ESPE) composites. Strain and displacement were determined using the 3D digital image correlation method based on two cameras with 1μm displacement sensitivity and 1600×1200 pixel resolution (Aramis, GOM). Microleakage along dentin axial and gingival cavity walls was measured under a stereomicroscope using a different set of teeth (N=8/group). Data were analyzed using analyses of variance with Tukey's post-test, Pearson correlation and paired t-test (α=0.05).



Strain of TEC Bulk, Filtek Bulk, Beautifil Bulk and Kalore was in the range of 1-1.5%. EverX and control composites showed 1.5-2% strain. Axial displacements were between 5μm and 30μm. The least strain was identified at 2mm below the occlusal surface in 4-mm but not in 2-mm layered composites. Greater microleakage occurred along the gingival than axial wall (p<0.05). No correlation was found between strain/displacements and microleakage axially (r2=0.082, p=0.821; r2=-0.2, p=0.605, respectively) or gingivally (r2=-0.126, p=0.729, r2=-0.278, p=0.469, respectively).



Strain i.e. volumetric shrinkage of sculptable bulk-fill and low-shrinkage composites was comparable to control composites but strain distribution across restoration depth differed. Marginal integrity was more compromised along the gingival than axial dentin wall.
University of Belgrade, School of Dental Medicine, DentalNet Research Group, Rankeova 4, 11000 Belgrade, Serbia. Electronic address: vesna.miletic@stomf.bg.ac.rs.
Vesna
V
Miletic
University of Pristina, School of Medicine, Dental Clinic, Anri Dinana St., 38220 Kosovska Mitrovica, Serbia.
Dejan
D
Peric
University of Belgrade, Innovation Center of Faculty of Mechanical Engineering, Kraljice Marije 16, 11120 Belgrade, Serbia.
Milos
M
Milosevic
University of Belgrade, School of Dental Medicine, DentalNet Research Group, Rankeova 4, 11000 Belgrade, Serbia; Vinča, Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, Belgrade 11001, Serbia.
Dragica
D
Manojlovic
University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, Belgrade 11120, Serbia.
Nenad
N
Mitrovic
D004396:Coloring Agents / Q000493:pharmacokinetics; D003188:Composite Resins; D003731:Dental Caries; D003764:Dental Materials; D003804:Dentin; D006801:Humans; D008422:Materials Testing
D004396:Coloring Agents; D003188:Composite Resins; D003764:Dental Materials
Bulk-fill; Composites; Giomer; Low-shrinkage; Microleakage; Shrinkage