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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Nanogel-Based Filler-Matrix Interphase for Polymerization Stress Reduction

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Author(s):
Fronza, B. M. [1] ; Rad, Y. [2] ; Shah, P. K. [3] ; Barros, M. D. [2] ; Giannini, M. [1] ; Stansbury, J. W. [2, 3]
Total Authors: 6
Affiliation:
[1] Univ Estadual Campinas, Piracicaba Dent Sch, Restorat Dent Dept, Piracicaba, SP - Brazil
[2] Univ Colorado, Craniofacial Biol Dept, Aurora, CO 80045 - USA
[3] Univ Colorado, Chem & Biol Engn, Boulder, CO 80309 - USA
Total Affiliations: 3
Document type: Journal article
Source: JOURNAL OF DENTAL RESEARCH; v. 98, n. 7, p. 779-785, JUL 2019.
Web of Science Citations: 0
Abstract

A novel filler-resin matrix interphase structure was developed and evaluated for dental composite restoratives. Nanogel additives were chemically attached to the filler surface to use this created interphase as a potential source of compliance to minimize stress development during polymerization. In addition, we evaluated the effects of free nanogel dispersion into the resin matrix, combined or not with nanogel-modified fillers. Nanogels with varied characteristics were synthesized (i.e., size, 5 and 11 nm; glass transition temperature, 28 degrees C to 65 degrees C). Glass fillers were treated with trimethoxyvinylsilane and further reacted with thiol-functionalized nanogels via a free radical thiol-ene reaction. gamma-Methacryloxypropyltrimethoxysilane-surface treated fillers were used as a control. Composites were formulated with BisGMA/TEGDMA resin blend with 60 wt% fillers with nanogel-modified fillers and/or free nanogel additives at 15 wt% in the resin phase. Polymerization kinetics, polymerization stress, volumetric shrinkage, and rheological and mechanical properties were evaluated to provide comprehensive characterization. Nanogel-modified fillers significantly reduced the polymerization stress from 2.2 MPa to 1.7 to 1.4 MPa, resulting in 20% stress reduction. A significantly greater nanogel content was required to generate the same magnitude stress reduction when the nanogels were dispersed only in the resin phase. When the nanogel-modified filler surface treatment and resin-dispersed nanogel strategies were combined, there was a stress reduction of 50% (values of 1.2 to 1.1 MPa). Polymerization rate and volumetric shrinkage were significantly reduced for systems with nanogel additives into the resin. Notably, the flexural modulus of the materials was not compromised, although a slight reduction in flexural strength associated with the nanogel-modified interphase was observed. Overall, modest amounts of free nanogel additives in the resin phase can be effectively combined with a limited nanogel content filler-resin interphase to lower volumetric shrinkage and dramatically reduce overall polymerization stress of composites. (AU)

FAPESP's process: 15/23104-1 - Approaches in filler particle and resin matrix interfacial design of dental composites
Grantee:Bruna Marin Fronza
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 16/05035-5 - Polymer brush surface modification for composite resin fillers
Grantee:Bruna Marin Fronza
Support type: Scholarships abroad - Research Internship - Doctorate