Scratch resistance of different silica filled resins for obturation materials

The authors have synthesised new silica filled polymeric resins for use as dental obturation materials. In contrast to earlier materials prepared for similar purposes, the present ones contain up to 80% silica nanoparticles providing the materials with improved mechanical properties. Scratch testing results show low values of the penetration depths. The ceramic concentrations used exceed a threshold concentration needed to change the mechanical properties from a soft polymer to a rigid ceramic. Further addition of silica has only insignificant effects on tribology. The penetration depths vary more or less linearly with the load, while viscoelastic recovery has a more complicated dependence on the load. These new materials have scratch resistance values in the range appropriate for applications as obturation materials.