Design of a thermosensitive ibuprofen-loaded nanogel as smart material applied as anti-inflammatory in tooth bleaching: An in vivo study

Abstract

The in vivo ability of thermosensitive nanogel containing ibuprofen for bioadhesion on the surface of teeth submitted to bleaching and drug delivery through dentinal tubules to the dental pulp are evaluated in Wistar rats. Drug-loaded self-assembled oil in water nanoemulsions present droplet size <150 nm and negative zeta potential. Nanoemulsions containing poloxamer 407 in the aqueous phase exhibit reduced droplet size, improved physical stability, controlled the thermosensitive viscosity, and slow drug release. Different treated animals' groups included a control group (CTRL); bleached animals (BLE) (37.5% H2O2, Pola Office Plus®, SDI); bleached animals treated with a conventional ibuprofen-loaded hydrogel (BLE + IBF-GEL), and bleached animals treated with thermosensitive ibuprofen-loaded nanogel (BLE + IBF-NEG). Compared to the BLE + IBF-GEL group, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images show the superior ability of BLE + IBF-NEG group to offer a physical barrier on the tooth surface, pores occlusion, and transport the fluorescent dye rhodamine B to dental pulp. Morphological analysis revealed the lowest inflammatory infiltrate scores and absence of necrosis for BLE + IBF-NEG group after 24 h and 14 days. Immunohistochemical studies reinforced this hypothesis. The experimental data presented in this study confirm the incredible potential for topical and easy application of a novel and smart nanogel, as analgesic and anti-inflammatory treatment for bleaching procedure.