Bioactive Minerals Research Articles

A Novel Biomineral Water Based Dental Cement

The area of cements in dentistry is steadily growing with the introduction of new systems that need to be cemented to the tooth, e.g. new inlays and crowns. With the better properties of the implants there is a need for new cements with high bond strength, good esthetic and mechanical properties. The bioactive minerals have not been explored as dental cement. This paper investigates the strength, setting time and film thickness of a novel dental cement based on the biomineral Marokite (calcium aluminate) as bonding system. The reactive Marokite powder is mixed with glass filler (ratio of 1.9 by volume) and water (ratio of 0.4 by weight) to a paste, which hardens within 6 minutes and has a working time of 2 minutes. The compressive strength reaches 143 MPa after 24 hours and the flexural strength almost 40 MPa. When the film thickness is measured at the end of the working time it is about 50 µm. Compared to glass ionomer cement (Fuji Cem) and zinc phosphate cement (Harvad) the biomineral system has higher strength and comparable setting time and film thickness. The investigation shows that it is feasible to develop dental cements based on biominerals, in this case a Marokite based material. The cement complies with the given standards.

Cyclosilicate nanocomposite: a novel resorbable bioactive tissue engineering scaffold for BMP and bone-marrow cell delivery.

Porous bioactive resorbable silica-calcium phosphate nanocomposite (SCPC) was prepared by a sintering technique. XRD analyses showed that the main crystalline phases of the SCPC are Na(3)CaPSiO(7) (clinophosinaite), beta-NaCaPO(4) (rhenanite), Na(2)CaSiO(4), and beta-quartz (SiO(2)). The clinophosinaite is a novel cyclosilicate bioactive mineral that enhanced the mechanical and bioactivity properties of the SCPC. TEM analysis showed that the grain sizes of the multiphase SCPC are in the nanometer scale. Moreover, the SCPC was engineered with nano- and microscale porosity. The SCPC had significantly higher compressive strength than porous hydroxyapatite (HA). FTIR analyses revealed the formation of biological hydroxyapatite layer on the SCPC surface after 4 days of immersion in SBF. When SCPC was loaded with rhBMP-2, it provided a superior release profile of biologically active rhBMP-2 compared to porous HA. Bone-marrow cells incubated with medium treated with the rhBMP-2 released from the SCPC-rhBMP-2 hybrid expressed significantly higher alkaline phosphatase activity than that expressed by cells incubated with media treated with rhBMP-2 released from HA-rhBMP-2. In addition, cells attached to the SCPC-rhBMP-2 hybrid produced mineralized extracellular matrix (ECM) and bone-like tissue that covered the material surface and filled pores in the entire thickness of the template after 3 weeks in culture. In contrary, cells attached to the HA-rhBMP-2 produced limited amount of unmineralized ECM after the same time period. Results of the study strongly suggest that the porous bioactive silica-calcium phosphate nanocomposite can serve as a delivery system for cells and biological molecules. The SCPC-rhBMP-2-marrow cell hybrid may serve as an alternative to autologous bone grafting.