TY  - JOUR
A1  - Holzmeister, Ib
A1  - Weichhold, Jan
A1  - Groll, Jürgen
A1  - Zreiqat,, Hala
A1  - Gbureck, Uwe
T1  - Hydraulic reactivity and cement formation of baghdadite
JF  - Journal of the American Ceramic Society
N2  - In this study, the hydraulic reactivity and cement formation of baghdadite (Ca\(_{3}\)ZrSi\(_{2}\)O\(_{9}\)) was investigated. The material was synthesized by sintering a mixture of CaCO\(_{3}\), SiO\(_{2}\), and ZrO\(_{2}\) and then mechanically activated using a planetary mill. This leads to a decrease in particle and crystallite size and a partial amorphization of baghdadite as shown by X-ray powder diffraction (XRD) and laser diffraction measurements. Baghdadite cements were formed by the addition of water at a powder to liquid ratio of 2.0 g/ml. Maximum compressive strengths were found to be ~2 MPa after 3-day setting for a 24-h ground material. Inductively coupled plasma mass spectrometry (ICP-MS) measurements showed an incongruent dissolution profile of set cements with a preferred dissolution of calcium and only marginal release of zirconium ions. Cement formation occurs under alkaline conditions, whereas the unground raw powder leads to a pH of 11.9 during setting, while prolonged grinding increased pH values to approximately 12.3.
KW  - baghdadite
KW  - bone cement
KW  - hydraulic reactivity
KW  - mechanical activation
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259457
VL  - 104
IS  - 7
ER  - 
TY  - JOUR
A1  - No, Young Jung
A1  - Holzmeister, Ib
A1  - Lu, Zufu
A1  - Prajapati, Shubham
A1  - Shi, Jeffrey
A1  - Gbureck, Uwe
A1  - Zreiqat, Hala
T1  - Effect of Baghdadite Substitution on the Physicochemical Properties of Brushite Cements
JF  - Materials
N2  - Brushite cements have been clinically used for irregular bone defect filling applications, and various strategies have been previously reported to modify and improve their physicochemical properties such as strength and injectability. However, strategies to address other limitations of brushite cements such as low radiopacity or acidity without negatively impacting mechanical strength have not yet been reported. In this study, we report the effect of substituting the beta-tricalcium phosphate reactant in brushite cement with baghdadite (Ca\(_3\)ZrSi\(_2\)O\(_9\)), a bioactive zirconium-doped calcium silicate ceramic, at various concentrations (0, 5, 10, 20, 30, 50, and 100 wt%) on the properties of the final brushite cement product. X-ray diffraction profiles indicate the dissolution of baghdadite during the cement reaction, without affecting the crystal structure of the precipitated brushite. EDX analysis shows that calcium is homogeneously distributed within the cement matrix, while zirconium and silicon form cluster-like aggregates with sizes ranging from few microns to more than 50 µm. X-ray images and µ-CT analysis indicate enhanced radiopacity with increased incorporation of baghdadite into brushite cement, with nearly a doubling of the aluminium equivalent thickness at 50 wt% baghdadite substitution. At the same time, compressive strength of brushite cement increased from 12.9 ± 3.1 MPa to 21.1 ± 4.1 MPa with 10 wt% baghdadite substitution. Culture medium conditioned with powdered brushite cement approached closer to physiological pH values when the cement is incorporated with increasing amounts of baghdadite (pH = 6.47 for pure brushite, pH = 7.02 for brushite with 20 wt% baghdadite substitution). Baghdadite substitution also influenced the ionic content in the culture medium, and subsequently affected the proliferative activity of primary human osteoblasts in vitro. This study indicates that baghdadite is a beneficial additive to enhance the radiopacity, mechanical performance and cytocompatibility of brushite cement
KW  - baghdadite
KW  - calcium phosphate cement
KW  - radiopacity
KW  - setting reaction
KW  - mechanical performance
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196980
SN  - 1996-1944
VL  - 12
IS  - 10
ER  -