[Reinforcing fillers in posterior composites: composition and interparticle spacing]

Interparticle spacing has been long recognized as a very important parameter in the design of composite resins, especially for those placed in the posterior region. The purpose of this study was to assess the interparticle spacing in seven posterior composite resins (Ful-Fil, P-10, P-30, Herculite, HSCUF-experimental, Estilux Posterior, Estilux Posterior XR1). Interparticle spacing was varying from 0.28-2.99 microns (Underwood method) to 0.34-3.40 microns (Fullman method). Laser diffraction particle size analysis was found inefficient for application in dental composite filler technology. In the tested materials the following types or reinforcing fillers were identified: SiO2, BaO, ZnO and AlSiO4.