Effect of a novel polymer modified nanofiller on fracture toughness of dental adhesives

Developing a novel dentin bonding system reinforced by a mixture of poly(methacrylic acid) grafted nanoclay and nanosilica was the main objective of this study. Poly (methacrylic acid) was grafted onto the pristine nanoclay surface in presence of nanosilica and characterized subsequently. The modified nanofiller was incorporated into an experimental dentin bonding system in different concentrations ranging from 0.2 wt.% to5 wt.%. The resulting dental adhesives were then photocured and fracture toughness of the cured adhesives was also measured and the exfoliation of nanoclays platelets in cured adhesives was investigated via TEM. According to the results, an exfoliated structure for modified nanofillers was observed. Incorporating 0.5 wt.% of modified nanofiller into the adhesive resulted in a significant increase in Fracture toughness