Effect of the Silanization of Aerosil OX50 in the Properties of Light-Cured Dental Composites

In this study, the surface of aerosil OX50 was treated with gamma-methacryloxypropyltrimethoxysilane in order to evaluate its effect on light-cured dental composites. Four composites were prepared with Bis-GMA/tetraethylene glycol dimethacrylate/gamma-methacryloxypropyltrimethoxysilane, Bis-GMA/tetraethylene glycol dimethacrylate, and a 45% treated or untreated aerosil OX50, using the camphorquinone/N,N-dimethylaminoethyl methacrylate pair as initiator. Evidence of filler silanization was provided by FTIR as a low-intensity absorption at 1707 cm-1 (carbonyl functional group) while thermogravimetric analysis showed a mass loss of approximately 2% associated with the decomposition of gamma-methacryloxypropyltrimethoxysilane. The experimental composites studied meet the requirements of the ISO 4049:2019 standard for depth of cure, water sorption, and solubility. The composites are shown to be thermally stable and presented a degree of conversion higher than 70%, being higher than that reported for many commercial composites. Based on the observed properties, the best formulations were those in which the silane is incorporated into the matrix and the filler was previously treated.