Titanium dioxide nanotubes with triazine-methacrylate monomer to improve physicochemical and biological properties of adhesives

Michele Stürmer; Isadora M Garcia; Virgínia S Souza; Fernanda Visioli; Jackson D Scholten; Susana M W Samuel; Vicente C B Leitune; Fabrício M Collares

doi:10.1016/j.dental.2020.11.004

Titanium dioxide nanotubes with triazine-methacrylate monomer to improve physicochemical and biological properties of adhesives

Dent Mater. 2021 Feb;37(2):223-235. doi: 10.1016/j.dental.2020.11.004. Epub 2020 Nov 24.

Authors

Michele Stürmer¹, Isadora M Garcia², Virgínia S Souza³, Fernanda Visioli⁴, Jackson D Scholten⁵, Susana M W Samuel⁶, Vicente C B Leitune⁷, Fabrício M Collares⁸

Affiliations

¹ Dental Materials Department, School of Dentistry, Federal University of Rio Grande do Sul. Ramiro Barcelos Street, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: mi_sturmer@hotmail.com.
² Dental Materials Department, School of Dentistry, Federal University of Rio Grande do Sul. Ramiro Barcelos Street, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: isadora.garcia@ufrgs.br.
³ Laboratory of Molecular Catalysis, Institute of Chemistry, Federal University of Rio Grande do Sul. Bento Gonçalves Avenue, 9500, Agronomia, 91501-970, Porto Alegre, RS, Brazil. Electronic address: vivi_qui@hotmail.com.
⁴ Oral Pathology Department, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: fevisioli@gmail.com.
⁵ Laboratory of Molecular Catalysis, Institute of Chemistry, Federal University of Rio Grande do Sul. Bento Gonçalves Avenue, 9500, Agronomia, 91501-970, Porto Alegre, RS, Brazil. Electronic address: jackson.scholten@ufrgs.br.
⁶ Dental Materials Department, School of Dentistry, Federal University of Rio Grande do Sul. Ramiro Barcelos Street, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: susana.samuel@ufrgs.br.
⁷ Dental Materials Department, School of Dentistry, Federal University of Rio Grande do Sul. Ramiro Barcelos Street, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: vicente.leitune@ufrgs.br.
⁸ Dental Materials Department, School of Dentistry, Federal University of Rio Grande do Sul. Ramiro Barcelos Street, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: fabricio.collares@ufrgs.br.

PMID: 33243438
DOI: 10.1016/j.dental.2020.11.004

Abstract

Objective: Formulate experimental adhesives containing titanium dioxide nanotubes (nt-TiO₂) or titanium dioxide nanotubes with a triazine-methacrylate monomer (nt-TiO₂:TAT) and evaluate the effect of these fillers on the physical, chemical, and biological properties of the adhesives.

Methods: First, nt-TiO₂ were synthesized via a hydrothermal method. The nt-TiO₂ were mixed with a triazine-methacrylate monomer (TAT) to formulate nt-TiO₂:TAT, which were characterized by transmission electron microscopy (TEM). The nt-TiO₂, TAT, and nt-TiO₂:TAT were evaluated via Fourier Transform Infrared, Ultraviolet-visible, and micro-Raman spectroscopies. An experimental adhesive resin was formulated with bisphenol A glycerolate dimethacrylates, 2-hydroxyethyl methacrylate, and photoinitiator/co-initiator system. nt-TiO₂ or nt-TiO₂:TAT were incorporated at 2.5 wt.% and 5 wt.% in the adhesive. The base resin without nt-TiO₂ or nt-TiO₂:TAT was used as a control group. The adhesives were evaluated for antibacterial activity, cytotoxicity, polymerization kinetics, degree of conversion (DC), Knoop hardness, softening in solvent (ΔKHN%), ultimate tensile strength (UTS), 24 h- and 1 year- microtensile bond strength (μ-TBS).

Results: TEM confirmed the nanotubular morphology of TiO₂. FTIR, UV-vis, and micro-Raman analyses showed the characteristic peaks of each material, indicating the impregnation of TAT in the nt-TiO₂. Adhesives with nt-TiO₂:TAT showed antimicrobial activity against biofilm formation compared to control (p < 0.05), without differences in the viability of planktonic bacteria (p > 0.05). All groups showed high percentages of pulp cell viability. The polymerization kinetics varied among groups, but all presented DC above 50%. The addition of 5 wt.% of nt-TiO₂ and both groups containing nt-TiO₂:TAT showed higher values of Knoop hardness compared to the control (p < 0.05). The groups with nt-TiO₂:TAT presented lower ΔKHN% (p < 0.05) and higher UTS (p < 0.05) than the control group. After one year, the group with 5 wt.% of nt-TiO₂, as well as both groups containing nt-TiO₂:TAT, showed higher μ-TBS than the control (p < 0.05).

Significance: The mixing of a triazine-methacrylate monomer with the nt-TiO₂ generated a filler that improved the physicochemical properties of the adhesive resins and provided antibacterial activity, which could assist in preventing carious lesions around tooth-resin interfaces. The set of physical, chemical, and biological properties of the formulated polymer, together with the greater stability of the bond strength over time, make nt-TiO₂:TAT a promising filler for dental adhesive resins.

Keywords: Antibacterial agents; Chemomechanical properties; Dentin bonding agents; Nanotechnology; Polymers.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Dental Bonding*
Dental Cements
Dentin-Bonding Agents
Materials Testing
Methacrylates
Nanotubes*
Resin Cements
Tensile Strength
Titanium
Triazines

Substances

Dental Cements
Dentin-Bonding Agents
Methacrylates
Resin Cements
Triazines
titanium dioxide
Titanium