Development of brushite particles synthesized in the presence of acidic monomers for dental applications.

Marina D S Chiari, Marcela C Rodrigues, Mirella F C Pinto, Douglas N Vieira, Flávio M Vichi, Oscar Vega, Wojciech Chrzanowski, Noriyuki Nagaoka, Roberto R Braga

Journal: Materials science & engineering. C, Materials for biological applications 2021;116():111178

PMID: 32806326

Full Text on Elsevier Science View on PubMed

Abstract

OBJECTIVES

To synthesize and characterize brushite particles in the presence of acidic monomers (acrylic acid/AA, citric acid/CA, and methacryloyloxyethyl phosphate/MOEP) and evaluate the effect of these particles on degree of conversion (DC), flexural strength/modulus (FS/FM) and ion release of experimental composites.

METHODS

Particles were synthesized by co-precipitation with monomers added to the phosphate precursor solution and characterized for monomer content, size and morphology. Composites containing 20 vol% brushite and 40 vol% reinforcing glass were tested for DC, FS and FM (after 24 h and 60 d in water), and 60-day ion release. Data were subjected to ANOVA/Tukey tests (DC) or Kruskal-Wallis/Dunn tests (FS and FM, alpha: 5%).

RESULTS

The presence of acidic monomers affected particle morphology. Monomer content on the particles was low (0.1-1.4% by mass). Composites presented similar DC. For FS/24 h, only the composite containing DCPD_AA was statistically similar to the composite containing 60 vol% of reinforcing glass (without brushite, "control"). After 60 days, all brushite-containing materials showed similar FS, statistically lower than the control composite (p<0.01). Composites containing DCPD_AA, DCPD_MOEP or DCPD_U ("unmodified") showed statistically similar FM/24 h, higher than the control composite. After prolonged immersion, all composites were similar to the control composite, except DCPD_AA. Cumulative ion release ranged from 21 ppm to 28 ppm (calcium) and 9 ppm to 17 ppm (phosphate). Statistically significant reductions in ion release between 15 and 60 days were detected only for the composite containing DCPD_MOEP.

SIGNIFICANCE

Acidic monomers added to the synthesis affected brushite particle morphology. After 60-day storage in water, composite strength was similar among all brushite-containing composites. Ion release was sustained for 60 days and it was not affected by particle morphology.

Address: University of São Paulo, Department of Biomaterials and Oral Biology, School of Dentistry, São Paulo, Brazil.; Cruzeiro do Sul University, São Paulo, São Paulo, Brazil.; University of São Paulo, Department of Fundamental Chemistry, Institute of Chemistry, São Paulo, Brazil.; Nuclear and Energy Research Institute, Center for Chemical and Environmental Technology, São Paulo, Brazil.; The University of Sydney, School of Pharmacy, Sydney, Australia.; Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama City, Okayama, Japan.; University of São Paulo, Department of Biomaterials and Oral Biology, School of Dentistry, São Paulo, Brazil. Electronic address: [email protected].

DOI: 10.1016/j.msec.2020.111178

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MeSH Terms: Calcium Phosphates, Composite Resins, Dental Materials, Flexural Strength, Materials Testing, Methacrylates, Pliability