Antibacterial response of oral microcosm biofilm to nano-zinc oxide in adhesive resin

Isadora Martini Garcia; AbdulRahman A Balhaddad; Maria S Ibrahim; Michael D Weir; Hockin H K Xu; Fabrício Mezzomo Collares; Mary Anne S Melo

doi:10.1016/j.dental.2020.11.022

Antibacterial response of oral microcosm biofilm to nano-zinc oxide in adhesive resin

Dent Mater. 2021 Mar;37(3):e182-e193. doi: 10.1016/j.dental.2020.11.022. Epub 2020 Dec 17.

Authors

Isadora Martini Garcia¹, AbdulRahman A Balhaddad², Maria S Ibrahim³, Michael D Weir⁴, Hockin H K Xu⁵, Fabrício Mezzomo Collares⁶, Mary Anne S Melo⁷

Affiliations

¹ Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil; Division of Biomaterials and Tissue Engineering, Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA. Electronic address: isadora.garcia@ufrgs.br.
² Ph.D. Program in Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Department of Restorative Dentistry, Umm Al-Qura University, College of Dentistry, Makkah, Saudi Arabia. Electronic address: abalhaddad@umaryland.edu.
³ Department of Preventive Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia. Electronic address: msibrahim@iau.edu.sa.
⁴ Division of Biomaterials and Tissue Engineering, Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Ph.D. Program in Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA. Electronic address: michael.weir@umaryland.edu.
⁵ Division of Biomaterials and Tissue Engineering, Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Ph.D. Program in Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA. Electronic address: hxu@umaryland.edu.
⁶ Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: fabricio.collares@ufrgs.br.
⁷ Ph.D. Program in Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA; Operative Dentistry Division, General Dentistry Department University of Maryland School of Dentistry, Baltimore, MD 21201, USA. Electronic address: mmelo@umaryland.edu.

PMID: 33342588
DOI: 10.1016/j.dental.2020.11.022

Abstract

Objective: Various nanoparticles are currently under investigation to impart biointeractivity for dental materials. This study aimed to: (1) formulate an experimental dental adhesive containing ZnO nanoparticles; (2) evaluate its chemical and mechanical properties; and (3) assess the antibacterial response against oral microcosm biofilm.

Methods: Nanosized ZnO was chemically and morphologically evaluated. ZnO was incorporated at 0 (G_CTRL), 2.5 (G_2.5%), 5 (G_5%) and 7.5 (G_5%) wt.% in an experimental dental adhesive. The adhesives were evaluated for the degree of conversion (DC), flexural strength (FS), and elastic modulus (E). The antibacterial activity was evaluated using a 48h-microcosm biofilm model after the formation of acquired pellicle on samples' surfaces. Colony-forming units (CFU), metabolic activity, and live/dead staining were assessed.

Results: Nanosized ZnO presented characteristic peaks of Zn-O bonds, and the particles were arranged in agglomerates. The DC ranged from 62.21 (±1.05) % for G_Ctrl to 46.15 (±1.23) % for G_7.5% (p<0.05). G_7.5% showed lower FS compared to all groups (p<0.05). Despite achieving higher E (p<0.05), G_2.5% did not show differences for G_Ctrl regarding the FS (p>0.05). G_7.5% had lower CFU/mL compared to G_Ctrl for mutans streptococci (p<0.05) and total microorganisms (p<0.05), besides presenting lower metabolic activity (p<0.05) and higher dead bacteria via biofilm staining.

Significance: The dental adhesives' physicochemical properties were similar to commercial adhesives and in compliance with ISO recommendations. G_7.5% restricted the growth of oral microcosm biofilm without impairing the physicochemical performance.

Keywords: Antibacterial agents; Biofilms; Composite resins; Dental caries; Dentin-bonding agents; Polymers.

Publication types

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

MeSH terms

Anti-Bacterial Agents / pharmacology
Biofilms
Dental Cements
Materials Testing
Methacrylates
Resin Cements
Streptococcus mutans
Zinc Oxide* / pharmacology

Substances

Anti-Bacterial Agents
Dental Cements
Methacrylates
Resin Cements
Zinc Oxide