Prevention of secondary caries using fluoride-loaded chitosan nanoparticle-modified glass-ionomer cement.

OBJECTIVE: To study the effect of incorporating chitosan and fluoride-loaded chitosan nanoparticles into a glass-ionomer cement (GIC) to prevent secondary caries. MATERIALS AND METHODS: A standard cervical cavity (mesio-distal width 6 mm, cervico-occlusal width 2 mm, and depth 2 mm) was prepared on 30 molars for the following restoration groups: group 1, conventional GIC restoration; group 2, chitosan (10%) modified GIC restoration; group 3, fluoride loaded chitosan nanoparticles (10%) modified GIC restoration. The restored teeth were subjected to 1,500 thermal cycles before undergoing a multi-species cariogenic biofilm challenge. The restored teeth were examined by micro-computed tomography (micro-CT), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). Data were analyzed by the one-way ANOVA, Tukey HDS, Kruskal Wallis, and Dunn's test. RESULTS: Micro-CT determined outer lesion depths for groups 1-3 were: 614 ± 20 µm, 589 ± 17 µm, and 560 ± 19 µm respectively. Both modifications with chitosan and fluoride-loaded chitosan nanoparticles significantly affected outer lesion depth (p < 0.05). The modification with fluoride-loaded chitosan nanoparticles statistically significantly decreased the outer lesion depth compared to all other groups (p < 0.05). SEM/EDX showed an increase of calcium, phosphorus, and fluoride at the root dentine adjacent to the restoration in groups 2 and 3 (modified GIC). This increase was statistically significantly higher in the group modified with fluorine-loaded nano chitosan particles compared to the other groups (p < 0.05). CONCLUSION: Incorporation of 10% chitosan and 10% fluoride-loaded chitosan nanoparticles into GIC restorative material can prevent secondary root caries development. 10% fluoride-loaded chitosan nanoparticles were more effective. CLINICAL SIGNIFICANCE: Glass ionomer cement modified with fluoride-loaded chitosan nanoparticles may be a promising restorative material in pediatric and preventive dentistry due to their controlled release properties.

In vitro and in vivo evaluation of microneedles coated with electrosprayed micro/nanoparticles for medical skin treatments.

AIM: Microneedles (MNs) create micropunctures and deliver drugs or nutrients deep into skin layer. We demonstrated that MNs, coated with electrosprayed nanoparticles loaded with functional molecules, are useful for transdermal delivery. METHODS: Electrospraying was utilised to generate drug-loaded nanoparticles and to create uniform coating on MNs. Process parameters and release kinetics were evaluated in vitro. The in vivo efficacy of insulin-coated MNs was investigated using diabetic rats. RESULTS: Electrosprayed micro/nanoparticles loaded with dye or insulin were coated on MNs with particle size of 515 ± 286 and 522 ± 261 nm, respectively. Optimally coated MNs resulted in >70% transfer rate into porcine skins. Insulin-coated MNs were applied to diabetic rats resulting in reduction of blood glucose levels fluctuations, compared to subcutaneous injections. CONCLUSIONS: Electrospraying is shown to be an effective method to coat MNs with drug-loaded nanoparticles. Coated MNs provide a promising platform for cosmetic, drug and protein delivery applications.