Biaxial flexural strength of new Bis-GMA/TEGDMA based composites with different fillers for dental applications

• Different kinds of filler particles were compared in a composite resins.
• Low particle-matrix coupling leads to low mechanical strength.
• However, strength of composites with tetrapodal zinc oxide fillers is increased.
• Functionalization with lauric acid decreases strength of composite resins.

ObjectiveThe aim of this study was to evaluate whether the mechanical properties of the modern dental composites can be improved by using tetrapodal ZnO particles as fillers in a Bis-GMA/TEGDMA matrix. Another aim was to test whether the mechanical properties of the composite are influenced by functionalization of the ZnO particles with lauric acid to achieve antibacterial activity.MethodsDifferent filler materials and particle shapes (spherical zirconia, spherical zinc oxide, tetrapodal zinc oxide) were used to produce Bis-GMA/TEGDMA based composites with a filler content of 40 wt.-% and 60 wt.-%, respectively. In addition, functionalization with lauric acid was investigated. For the biaxial flexural strength testing 104 test disks (N = 8) with a diameter of 15 mm and a thickness of 1.5 mm were produced.ResultsFunctionalization with lauric acid resulted in a decrease in biaxial flexural strength for all filler materials. The biaxial flexural strength decreased when using a higher filler content with spherical particles but increased when using tetrapodal zinc oxide particles.SignificanceA higher durability of the composites using tetrapodal zinc oxide particles. An antibacterial functionalization with lauric acid cannot be recommended as the mechanical stability of the composite will be reduced.