A Comparative Study of Low-Shrinkage Composite Resin

Objectives: Currently, there has been growing interest in new restorative materials that simplify the restoration process with dental composite.  Owing to the development of low-shrinkage bulk fill composites, it has been proposed that filling in a single layer results in adequate adaptation and polymerization of the restorative material and considerably reduces chair-time. In addition, another bulk fill restorative material also claim the possibility of filling the cavity without the need of a specific adhesive system. The aim of this study is to compare a low-shrinkage composite (Bulk-Fill Tetric N-Ceram/ Ivoclar Vivadent); a self-adhering flowable composite (Vertise Flow/Kerr) and a standard composite (Vitalescence/Ultradent) using micro-computed tomography (μCT) imaging to visualize and quantify their polymerization volumetric shrinkage.

Methods: Standardized class I cavities (2.5 mm depth X 5mm length X 5mm wide) were prepared in 24 extracted human third molars. They were divided into 3 groups (n=18): Group 1, Vitalescence with Peak adhesive system; Group 2, Tetric N-Ceram Bulk Fill with Tetric N-Bond Self-Etch; Group 3, Vertise Flow; Group 4. Each tooth was scanned via µCT at cavity preparation, after cavity filling and after light-cured polymerization. Acquired μCT data were imported into Amira software for analysis.

Results: The anticipated result of this comparison is that both of the materials (Bulk fill and self-adhering flowable composite) will perform well in the setting of minimizing shrinkage and marginal discrepancies in comparison to the standart composite. In terms of shrinkage, we anticipate that they will perform similarly well, despite of the difference in the consistencies of these two composites and the application/or absence of a specific adhesive system.

Conclusion: This experiment will identify the differences in efficacy of two new materials, as well as their advantages over regular composite resin.