Depth of Cure and Adaptation of Bulk-fill Resin Composites

Objectives: To determine the depth of cure and the adaptation to cavity walls of three Bulk-filled composite materials. Filtek Bulk Fill Flowable Resin Composite, SDR (Smart Dentin Replacement) Bulk Fill Flowable Resin Composite and Quixfil Bulk Fil Posterior Resin Composite with their own self etch adhesive system were used.
Methods: Thirty freshly extracted, intact human premolars were assigned for this study. Standardized Class II box-shape cavities were prepared on the proximal surface of the teeth. The dimensions of the preparation were 3x2x4.5 mm (buccolingual, mesiodistal widths and occluso-gingival depth). Premolars were randomly divided into three equal groups (G), of 10 teeth each, according to the material used. G1 was restored with Filtek bulk-filled, G2 was restored with SDR Flowable bulk- filled composite and G3 was restored with Quixfil bulk- filled composite. For the depth of cure assessment, Vickers microhardness tester was used. Each group was further subdivided into four equal subgroups according to depth of micro-hardness testing (D); (D₁) tested at a depth of 1mm, (D₂) at 2mm depth, (D₃) at 3mm and subgroup 4 (D₄) at 4mm depth. For adaptation assessment; tested materials were examined microscopically by Scanning electron Microscope. The width of the gap was measured between the adhesive bond and tooth structure at axial and gingival walls.
Results: Quixfil Bulk-fill showed significantly high depth of cure, followed by SDR and least was Filtek Bulk-fill in depth of cure. In adaptation; SDR revealed higher significance, followed by Filtek Bulk-fill and least Quixfil Bulk-fill.
Conclusions: 1. Condensable composite resin showed high depth of cure. 2. High molecular weight methacrylate monomer technology composite resin reveals good adaptation.