Efficacy, mineral content and biocompatibility of an experimental low-concentrated bleaching agent composed of hyaluronic acid and titanium dioxide nanoparticles co-doped with N and F.

Abstract

This study will evaluate the efficacy, mineral content, and biocompatibility (in vitro) of an experimental bleaching agent composed of hyaluronic acid (HA), NF_TiO2 nanoparticles (NPs), and low concentrations of hydrogen peroxide (HP). This project will be divided into two studies. In study 1, sound enamel specimens will be treated with: HP (hydrogen peroxide 35%, commercial control), (PH 6% Nano White DMC, commercial control); Carbomer 940 + PH (1,5 e 6%) + NF_TiO2 (5%); AH + PH (1,5 e 6%) + NF_TiO2 (5%); HA + HP (1.5, 3, and 6%) + NF_TiO2 (0, 5, and 10%), with and without LED light violet, and a negative control (no treatment). Bleaching will be performed in 3 sessions of 30 min with 7-days intervals. The following analysis will be performed: Phase 1: Characterization of experimental gels [pH measurement, particle size (polydispersity index, PdI), particle stability (zeta potential, PZ), and viscosity]; Phase 2: Color evaluation [spectrophotometer (L*, a*, b* parameters), whitening index (WID) and color change (”E)]; Phase 3: Mineral content [surface microhardness (KHN), energy dispersive spectroscopy (EDS)]; Phase 4: Surface Morphology [two-dimensional mean roughness (Ra) and scanning electron microscopy (SEM)]. Study 2 will evaluate the biocompatibility of MDPC-23 cells submitted to hyaluronic acid-containing experimental bleaching agents, NF_TiO2 NPs, and low-concentrated HP. In Study 2 MTT test will determine the metabolism of MDPC-23 cells after treatments (Phase 1). Besides, the concentration of PH present in the cell extract will be quantified (Phase 2) and the morphology of MDPC-23 cells will be determined after bleaching treatment with experimental gels (Phase 3). The results will be statistically analyzed, and the significant level will be set at 5%.