Chlorhexidine loaded MMT as dental composite filler: release evaluation

Abstract

Polymeric restorative materials are widely used, however polymerization shrinkage still stands as a major drawback as it allows microleakage, secondary caries, postoperative sensitivity and cusp deflection. A polymeric material with antimicrobial activity could be very useful in many dental procedures including adhesive cementation, sealants, dental adhesives and direct restorative material. The aim of this study was to develop nanocomposites for dental purposes composed by chlorhexidine loaded montmorillonite (Cloisite 30B) nanoparticles in a BisGMA / TEGDMA organic matrix. The specimens of experimental composites were synthesized with 10 % (w/w) of diacetate chlorhexidine incorporated in a MMT, as filler. The chlorhexidine release at 37 oC was evaluated in vitro in physiological solution at neutral pH for 366 hours. Drug content was estimated by UV spectroscopy at λ=255 nm. Significant drug release initiated after 96 hours and maintained throughout the experiment. In conclusion, the composite was capable of promoting chlorhexidine release over time, and such results in addition to the lack of significant weight loss (≤ 1.43 %) and the very low swelling (≤ 2.22 %) properties, revealed the strong potential of the developed composite for further dental and other biomaterial applications.