Physical and mechanical properties of a dental resin adhesive containing hydrophobic chitin nanocrystals

Francesco D'Acierno; Leslie Liu; Thanh-Dinh Nguyen; Carl A Michal; Regina G Palma-Dibb; Ricardo M Carvalho; Mark J MacLachlan

doi:10.1016/j.dental.2022.09.013

Physical and mechanical properties of a dental resin adhesive containing hydrophobic chitin nanocrystals

Dent Mater. 2022 Dec;38(12):1855-1865. doi: 10.1016/j.dental.2022.09.013. Epub 2022 Oct 4.

Authors

Francesco D'Acierno¹, Leslie Liu², Thanh-Dinh Nguyen³, Carl A Michal⁴, Regina G Palma-Dibb⁵, Ricardo M Carvalho⁶, Mark J MacLachlan⁷

Affiliations

¹ Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Department of Physics and Astronomy, The University of British Columbia, 6224 Agricultural Rd, Vancouver, BC V6T 1Z1, Canada. Electronic address: fradaci@chem.ubc.ca.
² Department of Oral Biological and Medical Sciences, The University of British Columbia, 2151 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada. Electronic address: leslie.liu@alumni.ubc.ca.
³ Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada. Electronic address: ntdinhc@gmail.com.
⁴ Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Department of Physics and Astronomy, The University of British Columbia, 6224 Agricultural Rd, Vancouver, BC V6T 1Z1, Canada. Electronic address: michal@physics.ubc.ca.
⁵ Department of Operative Dentistry, University of São Paulo, Av do Café S/N, Ribeirão Preto, SP, Brazil. Electronic address: rgpalma@gmail.com.
⁶ Department of Oral Biological and Medical Sciences, The University of British Columbia, 2151 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada. Electronic address: rickmc@dentistry.ubc.ca.
⁷ Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Stewart Blusson Quantum Matter Institute, The University of British Columbia, 2355 East Mall, Vancouver, BC V6T 1Z4, Canada; WPI Nano Life Science Institute, Kanazawa University, Kanazawa 920-1192, Japan; BioProducts Institute, The University of British Columbia, 2385 Agronomy Rd, Vancouver, BC V6T 1Z4, Canada. Electronic address: mmaclach@chem.ubc.ca.

PMID: 36202660
DOI: 10.1016/j.dental.2022.09.013

Abstract

Objectives: In this paper we propose embedding natural fillers, such as pristine and functionalized chitin nanocrystals, into resin adhesives to produce photopolymerizable dental filled adhesives with enhanced biocompatibility, hydrophobicity, mechanical resistance, and anti-bacterial properties.

Methods: Chitin nanocrystals (ChNC) were functionalized with decanoyl chloride and methacrylic anhydride to produce ChNC-C10 and ChNC-MA, respectively. These hydrophobically functionalized chitin nanocrystals were incorporated into a resin adhesive at concentrations of 0.5-3.0 wt% to assess the materials' physical and mechanical properties through Fourier-transform infrared (FTIR) spectroscopy, solid-state NMR spectroscopy, X-ray diffraction (XRD), elemental analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), flexural strength, microhardness, and water sorption tests.

Results: The analytical techniques confirmed the successful preparation of chitin nanocrystals from commercial chitin powder derived from shrimp shells and the efficient hydrophobization of their surface. Electron microscope images indicated that the increased hydrophobicity of ChNC-C10 promotes the formation of layered structures throughout the resin adhesive, while ChNC-MA tends to form aggregates in the matrix. Adhesives filled with ChNC-C10 enhanced their flexural strength, microhardness, and thermal stability and decreased their water sorption and degree of conversion. Adhesives filled with ChNC-MA resulted in improvements in microhardness, in water sorption and degree of conversion, although they did not exhibit augmentation of their flexural strength and thermal stability.

Significance: In light of the improved physical and mechanical properties with respect to the control, resin adhesives filled with anti-bacterial chitin nanocrystals are promising new materials for dental applications, especially those filled with low/moderate amounts of ChNC-C10.

Keywords: Adhesive; Chitin nanocrystals; Composite resin; Dental material; Functionalization.

Publication types

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

MeSH terms

Chitin
Composite Resins / chemistry
Dental Cements* / chemistry
Hydrophobic and Hydrophilic Interactions
Materials Testing
Nanoparticles* / chemistry
Resin Cements / chemistry
Resins, Synthetic / chemistry
Surface Properties
Water / chemistry

Substances

Dental Cements
Chitin
Resins, Synthetic
Water
Resin Cements
Composite Resins