Rafael Menezes-Silva1, Bruna Medeiros Bertol de Oliveira2, Paulo Henrique Martins Fernandes3, Lívia Yukari Shimohara3, Fabiano Vargas Pereira4, Ana Flávia Sanches Borges3, Marília Afonso Rabelo Buzalaf5, Renata Corrêa Pascotto2, Sharanbir K Sidhu6, Maria Fidela de Lima Navarro3. 1. Department of Dental Materials, Endodontics and Operative Dentistry, Bauru School of Dentistry-FOB-USP, Al. Octávio Pinheiro Brisolla, 9-75, 17012-901, Bauru, SP, Brazil. Electronic address: rafa18ms@hotmail.com. 2. Department of Dentistry, State University of Maringa, Av. Mandacaru, 1550, 87080-000, Maringá, PR, Brazil. 3. Department of Dental Materials, Endodontics and Operative Dentistry, Bauru School of Dentistry-FOB-USP, Al. Octávio Pinheiro Brisolla, 9-75, 17012-901, Bauru, SP, Brazil. 4. Department of Chemistry, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, 31270-901, Belo Horizonte, MG, Brazil. 5. Department of Biological Sciences, Bauru School of Dentistry-FOB-USP, Al. Octávio Pinheiro Brisolla, 9-75, 17012-901, Bauru, SP, Brazil. 6. Institute of Dentistry, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, Turner Street, London, E1 2AD, UK.
Abstract
OBJECTIVE: Glass-ionomer cements (GICs) modified with cellulose nanocrystals (CNs) were characterized and evaluated for compressive strength (CS), diametral tensile strength (DTS) and fluoride release (F-). METHODS: Commercially available GICs (Maxxion, Vidrion R, Vitro Molar, Ketac Molar Easy Mix and Fuji Gold Label 9) were reinforced with CNs (0.2% by weight). The microstructure of CNs and of CN-modified GICs were evaluated by transmission electron microscopy (TEM) and by scanning electron microscopy (SEM) while chemical characterization was by Fourier transform infrared spectroscopy (FTIR). Ten specimens each of the unmodified (control) and CN-modified materials (test materials) were prepared for CS and DTS testing. For the fluoride release evaluation, separate specimens (n=10) of each test and control material were made. The results obtained were submitted to the t-test (p<0.05). RESULTS: The CN reinforcement significantly improved the mechanical properties and significantly increased the F- release of all GICs (p<0.05). The GICs with CNs showed a fibrillar aggregate of nanoparticles interspersed in the matrix. The compounds with CNs showed a higher amount of C compared to the controls due to the organic nature of the CNs. It was not possible to identify by FTIR any chemical bond difference in the compounds formed when nanofibers were inserted in the GICs. SIGNIFICANCE: Modification of GICs with CNs appears to produce promising restorative materials.
OBJECTIVE: Glass-ionomer cements (GICs) modified with cellulose nanocrystals (CNs) were characterized and evaluated for compressive strength (CS), diametral tensile strength (DTS) and fluoride release (F-). METHODS: Commercially available GICs (Maxxion, Vidrion R, Vitro Molar, Ketac Molar Easy Mix and Fuji Gold Label 9) were reinforced with CNs (0.2% by weight). The microstructure of CNs and of CN-modified GICs were evaluated by transmission electron microscopy (TEM) and by scanning electron microscopy (SEM) while chemical characterization was by Fourier transform infrared spectroscopy (FTIR). Ten specimens each of the unmodified (control) and CN-modified materials (test materials) were prepared for CS and DTS testing. For the fluoride release evaluation, separate specimens (n=10) of each test and control material were made. The results obtained were submitted to the t-test (p<0.05). RESULTS: The CN reinforcement significantly improved the mechanical properties and significantly increased the F- release of all GICs (p<0.05). The GICs with CNs showed a fibrillar aggregate of nanoparticles interspersed in the matrix. The compounds with CNs showed a higher amount of C compared to the controls due to the organic nature of the CNs. It was not possible to identify by FTIR any chemical bond difference in the compounds formed when nanofibers were inserted in the GICs. SIGNIFICANCE: Modification of GICs with CNs appears to produce promising restorative materials.
Authors: Fernanda M Tsuzuki; Renata C Pascotto; Luis C Malacarne; Antonio C Bento; Antonio Medina Neto; Lidiane Vizioli de Castro-Hoshino; Monique Souza; John W Nicholson; Mauro L Baesso Journal: Biomater Investig Dent Date: 2021-04-01