Microhardness and Fluoride Release of Glass Ionomer Cement Modified with a Novel Al+3 Complex to Enhance Its Antimicrobial Activity

Samy M El-Safty; Nadia El-Wakiel; Gehan El-Oleimy; Mohamed Gaber; Yusif S El-Sayed

doi:10.1155/2021/1925388

Microhardness and Fluoride Release of Glass Ionomer Cement Modified with a Novel Al⁺³ Complex to Enhance Its Antimicrobial Activity

Int J Biomater. 2021 Oct 23:2021:1925388. doi: 10.1155/2021/1925388. eCollection 2021.

Authors

Samy M El-Safty¹, Nadia El-Wakiel², Gehan El-Oleimy¹, Mohamed Gaber², Yusif S El-Sayed²

Affiliations

¹ Department of Dental Biomaterials, Faculty of Dentistry, Tanta University, Tanta 31527, Egypt.
² Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt.

Abstract

Objectives: To synthesize and characterize a novel Al⁺³ complex with 2-(2-hydroxyphenyl)-1H-benzimidazole (HL) to be added to a restorative glass ionomer cement (GIC) to enhance its antimicrobial activities and to evaluate the Vickers microhardness (HV) and fluoride release (FR) of the modified GIC.

Materials and methods: Al⁺³ complex was synthesized by the addition of 1 mmol (0.210 g) of HL to 1 mmol (0.342 g) of aluminum sulfate in ethanol. The resulting solution was then refluxed under stirring for 24 h and then collected by filtration and dried in a vacuum desiccator over an anhydrous CaCl₂. Characterization of Al⁺³ complex was carried out by Fourier transform infrared spectroscopy (FTIR), elemental microanalysis, thermal gravimetric analysis (TGA), molar conductance, ¹H NMR spectra, and electron impact-mass spectrometry. The antimicrobial activity of Al⁺³ complex-modified GIC (Al-GIC) was studied by the "cut plug method" against Gram-negative bacteria (Acinetobacter baumannii) and Gram-positive bacteria (Staphylococcus aureus, Enterococcus, and Streptococcus mutants) and fungi (Candida albicans). HV was evaluated by a digital microhardness tester (Zwick/Roell, Indentec, ZHVμ-S, West Midlands, England). Fluoride levels in ppm were obtained using the ion-selective electrode connected to a digital meter. A one-way ANOVA and Bonferroni test were used to analyze the data with the significance level established at p ≤ 0.05.

Results: Synthesis of Al⁺³ complex was confirmed by FTIR, elemental microanalysis TGA, molar conductance, ¹H NMR spectra, and electron impact-mass spectrometry. Al-GICs exhibited an enhanced antibacterial activity against all studied microorganisms as confirmed by the growth of inhibition zones compared to control GIC (C-GIC). Though there was a slight reduction in HV and FR with increasing the added percent of Al⁺³ complex, no significant differences were found between the studied groups.

Conclusions: Addition of Al⁺³ complex to GIC powder enhanced the antimicrobial activity of GIC materials. As there was a negligible insignificant reduction in HV and FR upon the addition of Al⁺³ complex, Al-GICs can be used with a guaranteed degree of clinical success.