Formulation of pH-sensitive chlorhexidine-loaded/mesoporous silica nanoparticles modified experimental dentin adhesive

Mater Sci Eng C Mater Biol Appl. 2021 Mar;122:111894. doi: 10.1016/j.msec.2021.111894. Epub 2021 Jan 23.

Abstract

We formulated a pH-sensitive chlorhexidine-loaded mesoporous silica nanoparticles (MSN) modified with poly-(lactic-co-glycolic acid) (CHX-loaded/MSN-PLGA) and incorporated into experimental resin-based dentin adhesives at 5 and 10 wt%. Nanocarriers were characterized in terms of morphology, physicochemical features, spectral analyses, drug-release kinetics at varying pH and its effect on dentin-bound proteases was investigated. The modified dentin adhesives were characterized for cytotoxicity, antimicrobial activity, degree of conversion (DC) along with CHX release, micro-tensile bond strength (μTBS) and nano-leakage expression were studied at different pH values and storage time. CHX-loaded/MSN-PLGA nanocarriers exhibited a significant pH-dependent drug release behavior than CHX-loaded/MSN nanocarriers without PLGA modification. The highest percentage of CHX release was seen with 10 wt% CHX-loaded/MSN-PLGA doped adhesive at a pH of 5.0. CHX-loaded/MSN-PLGA modified adhesives exhibited more profound antibiofilm characteristics against S. mutans and more sustained CHX-release which was pH dependent. After 6 months in artificial saliva at varying pH, the 5 wt% CHX-loaded/MSN-PLGA doped adhesive showed excellent bonding under SEM/TEM, higher μTBS, and least nano-leakage expression. The pH-sensitive CHX-loaded/MSN-PLGA could be of crucial advantage for resin-dentin bonding applications especially in reduced pH microenvironment resulting from biofilm formation; and the activation of dentin-bound proteases as a consequence of acid etching and acidic content of bonding resin monomers.

Keywords: Chlorhexidine; Dentin bonding; Drug delivery; Mesoporous silica nanoparticles; pH variation.

MeSH terms

  • Chlorhexidine
  • Dental Bonding*
  • Dentin
  • Hydrogen-Ion Concentration
  • Materials Testing
  • Nanoparticles*
  • Resin Cements
  • Silicon Dioxide
  • Tensile Strength

Substances

  • Resin Cements
  • Silicon Dioxide
  • Chlorhexidine