Mechanical characterization and ion release of bioactive dental composites containing calcium phosphate particles

Author(s)

Natale, Livia C. ^[1] ; Rodrigues, Marcela C. ^[1] ; Alania, Yvette ^[1] ; Chiari, Marina D. S. ^[1] ; Boaro, Leticia C. C. ^[2] ; Cotrim, Marycel ^[3] ; Vega, Oscar ^[3] ; Braga, Roberto R. ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Dent, Dept Biomat & Oral Biol, Sao Paulo - Brazil

^[2] Univ Santo Amaro, Sao Paulo - Brazil

^[3] Nucl & Energy Res Inst, Ctr Chem & Environm Technol, Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS; v. 84, p. 161-167, AUG 2018.
• Web of Science Citations: 4

Abstract

Objective: to verify the effect of the addition of dicalcium phosphate dihydrate (DCPD) particles functionalized with di- or triethylene glycol dimethacrylate (DEGDMA or TEGDMA) on the degree of conversion (DC), post-gel shrinkage (PS), mechanical properties, and ion release of experimental composites. Methods: Four composites were prepared containing a BisGMA/TEGDMA matrix and 60 vol% of fillers. The positive control contained only barium glass fillers, while in the other composites 15 vol% of the barium was replaced by DCPD. Besides the functionalized particles, non-functionalized DCPD was also tested. DC after 24 h (n = 3) was determined by FTIR spectroscopy. The strain gage method was used to obtain PS 5 min after photoactivation (n = 5). Flexural strength and modulus (n = 10) were calculated based on the biaxial flexural test results, after specimen storage for 24 h or 60 days in water. The same storage times were used for fracture toughness testing (FT, n = 10). Calcium and phosphate release up to 60 days was quantified by ICP-OES (n = 3). Data were analyzed by ANOVA/Tukey test (alpha: 5%). Results: Composites containing functionalized DCPD presented higher DC than the control (p < 0.001). The material containing DEGDMA-functionalized particles showed higher PS than the other composites (p < 0.001). After 60 days, only the composite with DEGDMA-functionalized DCPD presented fracture strength similar to the control, while for flexural modulus only the composite with TEGDMA-functionalized particles was lower than the control (p < 0.001). FT of all composites containing DCPD was higher than the control after 60 days (p < 0.005). Calcium release was higher for the composite with non-functionalized DCPD at 15 days and no significant reductions were observed for composites with functionalized DCPD during the observation period (p < 0.001). For all the tested composites, phosphate release was higher at 15 days than in the subsequent periods, and no difference among them was recorded at 45 and 60 days (p < 0.001). Conclusions: DCPD functionalization affected all the studied variables. The composite with DEGDMA-functionalized particles was the only material with strength similar to the control after 60 days in water; however, it also presented the highest shrinkage. The presence of DCPD improved FT, regardless of functionalization. DCPD functionalization reduced ion release only during the first 15 days. (AU)

• FAPESP's process: 15/15019-4 - Development of functionalized calcium phosphate nanoparticles for use in resin-based dental composites
• Grantee: Roberto Ruggiero Braga
• Support Opportunities: Regular Research Grants