Thuydung Do1, Brent Church1, Crisnicaw Veríssimo2, Steven P Hackmyer1, Daranee Tantbirojn3, James F Simon3, Antheunis Versluis4. 1. Department of Pediatric Dentistry, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tenn., USA. 2. Department of Restorative Dentistry and Dental Materials, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil. 3. Department of Restorative Dentistry, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tenn., USA. 4. Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tenn., USA. antheun@uthsc.edu.
Abstract
PURPOSE: Evaluate cuspal flexure caused by polymerization shrinkage stress, bond integrity, and depth-of-cure of bulk-fill composites. METHODS: Twenty-eight extracted permanent molars were mounted in stainless steel rings. Slot-shaped Class II mesio-occlusal-distal preparations (four mm deep) were restored with Filtek Supreme Ultra (control; two two-mm increments) and bulk-fill composites (Tetric EvoCeram, Venus, Filtek Bulk Fill). The teeth were digitized using a 3D scanner before and after restoration. Before- and after-restoration scans were aligned, and cuspal flexure was calculated. Bond integrity along occlusal interfaces was assessed by dye penetration and measured after overnight immersion in basic fuchsin dye and cross-sectioning. Depth-of-cure was determined on the cross-sections using Vickers hardness. Statistical analysis was performed with one-way analysis of variance. RESULTS: All composites caused inward cuspal flexure (10.4 to 13.6 μm). No statistical difference in flexure was found among the composites (P=.07). No significant difference in microhardness at any restoration depths was found for any composite (.35<P<.99). Dye penetration showed comparable bonding along occlusal interfaces for the tested composites. CONCLUSIONS: Bulk-fill composites cured all the way through four-mm restoration depths. Cuspal flexure, caused by polymerization shrinkage, and bond integrity were not different between teeth restored with the bulk-fill and conventional incrementally placed restorative composites.
PURPOSE: Evaluate cuspal flexure caused by polymerization shrinkage stress, bond integrity, and depth-of-cure of bulk-fill composites. METHODS: Twenty-eight extracted permanent molars were mounted in stainless steel rings. Slot-shaped Class II mesio-occlusal-distal preparations (four mm deep) were restored with Filtek Supreme Ultra (control; two two-mm increments) and bulk-fill composites (Tetric EvoCeram, Venus, Filtek Bulk Fill). The teeth were digitized using a 3D scanner before and after restoration. Before- and after-restoration scans were aligned, and cuspal flexure was calculated. Bond integrity along occlusal interfaces was assessed by dye penetration and measured after overnight immersion in basic fuchsin dye and cross-sectioning. Depth-of-cure was determined on the cross-sections using Vickers hardness. Statistical analysis was performed with one-way analysis of variance. RESULTS: All composites caused inward cuspal flexure (10.4 to 13.6 μm). No statistical difference in flexure was found among the composites (P=.07). No significant difference in microhardness at any restoration depths was found for any composite (.35<P<.99). Dye penetration showed comparable bonding along occlusal interfaces for the tested composites. CONCLUSIONS: Bulk-fill composites cured all the way through four-mm restoration depths. Cuspal flexure, caused by polymerization shrinkage, and bond integrity were not different between teeth restored with the bulk-fill and conventional incrementally placed restorative composites.
Authors: Vilhelm G Ólafsson; André V Ritter; Edward J Swift; Lee W Boushell; Ching-Chang Ko; Gabrielle R Jackson; Sumitha N Ahmed; Terence E Donovan Journal: J Esthet Restor Dent Date: 2017-10-16 Impact factor: 2.843