Title: 0581 - Bioactive Composites Containing Calcium Phosphate Particles: Mechanical Properties and Ion Release


Livia Natale, University of São Paulo
Marcela Rodrigues, Universidade Cruzeiro do Sul
Yvete Alania, University of São Paulo
Marina Chiari, University of São Paulo
Marycel Cotrim, Instituto de Pesquisas Energéticas e Nucleares
Oscar Vega, Instituto de Pesquisas Energéticas e Nucleares
Roberto Braga (Presenter)
University of São Paulo


Objectives: The objective of this study was to compare the mechanical properties and ion release of composites containing different calcium phosphate (CaP) particles, namely, non-functionalized (NF), functionalized with triethylene glycol dimethacrylate (TF) or diethylene glycol dimethacrylate (DF). The null hypothesis was that particle functionalization would not affect composite behavior.

Methods: Dicalcium phosphate dihydrate particles (DCPD) were obtained by sol-gel synthesis. For the functionalized particles, DEGDMA or TEGDMA was added to one of the precursor solutions. Composites were formulated with 15vol% DCPD, 45vol% barium glass and 40vol% BisGMA/TEGDMA matrix. Camphorquinone and tertiary amine (EDMAB) were added as photoinitiators. A composite containing 60vol% of barium glass was tested as control. Biaxial flexural test specimens (12x1 mm, n=10) stored for 24h or 60 days in water were tested in a “piston on three spheres” jig. Ca and P release from specimens stored in saline solution (pH 7) up to 60 days were determined by spectrometry (ICP-OES, n=5). Data were analyzed by two-way ANOVA/Tukey test (alpha: 5%).

Results: Mechanical properties are shown in the Table. DCPD type affected initial flexural strength only (DF>TF, p<0.05). After 60d-storage, only NF was similar to the control. Flexural modulus was not affected by the presence of DCPD or storage time (p>0.05). Ca concentrations (ppm) decreased from 1.8-3.9 (15d) to 1.3–1.7 (60d), while P concentrations decreased from 0.4-1.0 (15d) to 0.1-0.2 (60d), with no statistically significant differences among composites at any given time (p>0.05). NF showed a 66% reduction in Ca release between 15d and 60d, while DF and TF showed 32% and 28% reductions, respectively. For P, the reductions observed between 15d and 60d were 80% (NF), 75% (DF) and 66% (TF).

Conclusions: Within the limitations of this study, it is possible to conclude that only composite initial strength was affected by DCPD functionalization.


Composites Biaxial flexural strength (MPa) Flexural modulus (GPa)
24 hours 60 days 24 hours 60 days
Control (60vol% barium glass) 114.9 (17.9) ABa 125.9 (30.8) Aa 11.0 (2.2) Aa 15.6 (1.5) Aa
NF (15 vol% non-functionalized DCPD + 45 vol% barium glass) 106.7 (14.5) ABa 96.0 (13.0) ABa 13.3 (2.1) Aa 14.8 (5.0) Aa
DF (15 vol% DEGDMA-functionalized DCPD + 45 vol% barium glass) 118.2 (27.4) Aa 92.5 (31.9) Ba 13.6 (3.8) Aa 11.8 (3.6) Aa
TF (15 vol% TEGDMA-functionalized DCPD + 45 vol% barium glass) 87.4 (16.5) Ba 94.1 (16.8) Ba 13.9 (4.4) Aa 11.2 (4.8) Aa

This abstract is based on research that was funded entirely or partially by an outside source:
FAPESP 2015/15019-4

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: None