Flexural strength and microhardness of bulk-fill restorative materials

Author(s)

de Mendonca, Beatriz Curvello ; Soto-Montero, Jorge Rodrigo ; de Castro, Eduardo Fernandes ; Pecorari, Vanessa Gallego Arias ; Rueggeberg, Frederick Allen ; Giannini, Marcelo

• Document type: Journal article
• Source: Journal of Esthetic and Restorative Dentistry; v. 33, n. 4, p. 8-pg., 2021-03-05.

Abstract

Background Bulk-fill materials can facilitate the restorative procedure mainly for deep and wide posterior cavities. The purpose of this study was to evaluate flexural strength (biaxial flexural strength [BFS]) and microhardness (Knoop microhardness [KHN]) at different depths of bulk-fill materials. Methods Five bulk-fill materials were tested: two light-curable composite resins, one dual-cure composite, one bioactive restorative, and a high-viscosity glass ionomer. A conventional composite was used as control. BFS and KHN were tested at different depths. Data was analyzed by two- and one-way ANOVAs, respectively and Tukey's post-hoc (alpha=0.05). Results The high-viscosity glass ionomer material presented the lowest BFS at all depths. KHN for the two light-curable and the dual-cure bulk-fill resin composites was reduced following an increase in restoration depth, while the conventional composite, the bioactive material, and the high-viscosity glass ionomer were not affected. Conclusion There are differences in the properties of the tested materials at 4 mm depth, showing that the studied properties of some materials vary according to the cavity depth, although the results are material dependent. Clinical Significance Mechanical properties of light-cured, bulk-fill materials may be affected by inadequate polymerization. Clinicians should consider complementary strategies to achieve adequate polymerization at high-increment depths. (AU)

• FAPESP's process: 17/04348-2 - Evaluation of physical and mechanical properties of bulk-fill restorative materials
• Grantee: Beatriz Curvello de Mendonça
• Support Opportunities: Scholarships in Brazil - Master