Monodisperse silica-filled composite restoratives mechanical and light transmission properties

Abstract

Objectives: The aim of this study was to formulate resin-based composites using spherical silica particulate fillers with graded size (75, 150, 350, 500, and 1000nm), and to evaluate the influence of their size and loading on the mechanical and light transmission properties of the resulting material.

Methods: A series of five spherical silica fillers were synthesized, and then formulated with BisGMA/TEGDMA or UDMA/TEGDMA resins. These were then tested for maximum filler loading, flexural strength and modulus, as well as transparency and depth of cure.

Results: Low dispersity spherical silica particles of 75, 150, 350, 500, and 1000nm were synthesized. Maximum loading was 70wt% for the three largest particle, and decreased for the smaller sizes, where UDMA-based resins allowed slightly higher loading. When maximally loaded, the largest particle sizes produced the highest flexural properties. However, when using the same loading, all filler sized produced similar flexural strengths and moduli. The optical properties and depth of cure were increased as the filler size decreased.

Significance: While hybrid filler particles are the norm in commercial materials, by studying and understanding the influence of individual components on the material properties, we can finely tune the properties of the materials as desired.

Keywords: Dental restorative; Depth of cure; Flexural; Refractive index; Size effect; Spherical.