The effect of ball milling grinding pathways on the bulk and reactivity properties of calcium phosphate cements

Abstract

Calcium phosphate cements (CPCs) are significant alternatives to autologous bone grafting. CPCs can be composed of biphasic or multiphase calcium phosphate (CaP) compounds. A common way to process CPCs is by ball milling. Ball milling can be used for grinding or mechanosynthesis. The aim of this study was to determine the effect of well-defined ball milling grinding parameters, applied via different milling pathways, on the properties of CPCs. Starting CaP compounds used included α-tricalcium phosphate, dicalcium phosphate anhydrous and precipitated hydroxyapatite. Scanning electron microscopy showed changes in the powder morphology, which were related to the behavior of the starting CaP materials. Specific surface area (SSA) and particle size (PS) measurements exposed the effect of ball milling on the CaP compounds and CPC powders. X-ray diffraction revealed no effect of ball milling pathways or milling time on the composition of CPCs or the starting materials, but affected their crystallographic properties. No contamination of the milling media or transformation into an amorphous calcium phosphate compound was found. The milling pathways affected setting and cohesion. Fourier transform infrared spectroscopy (FTIR) revealed differences on the CPC v₄-PO₄³⁻ bands according to the interaction, created between the CaP compounds by the milling pathways. FTIR confirmed that the milling pathways changed the crystallographic properties. This study demonstrates that the pathways used for milling grinding modify the PS, SSA, and crystallographic properties of the powders, without affecting their composition. These modifications affected the bulk and reactivity properties of the CPCs by creating different setting and cohesion behaviors.

Bulk physicochemical, interconnectivity, and mechanical properties of calcium phosphate cements–fibrin glue composites for bone substitute applications

“…CPC powder consisted of 85 wt % alpha‐tricalcium phosphate (α‐TCP; CAM Bioceramics BV, The Netherlands), 10 wt % dicalcium phosphate anhydrous (DCPA; JT Baker Chemical, USA) and 5 wt % precipitated hydroxyapatite (pHA; Merck, Germany). These powders were sequentially ball‐milled 27. Briefly, CPC powders were ball‐milled (Pulverisette 6; FRITSCH, Germany) at 500 rpm and under dry atmospheric conditions.…”

“…α‐TCP powders were first milled for 4.5 h. Then, DCPA and pHA powders were added to the milled α‐TCP and everything was milled for one additional hour. After sequential milling, the CPC powders present a particle size around 3 μm and a specific surface area around 5.90 m 2 /g 27. FG components were obtained from a commercially available product, i.e.…”

An injectable calcium phosphate cement for the local delivery of paclitaxel to bone

“…The reasons for this is that mixing of CaP compounds in combination with the subsequent process creates an injectable CPC that situates itself between the requirements for clinical applications, i.e. setting time, cohesion, reactivity and mechanical properties [15,23,24]. The CPC used here hardens by a dissolution-precipitation mechanism [15,23].…”

“…setting time, cohesion, reactivity and mechanical properties [15,23,24]. The CPC used here hardens by a dissolution-precipitation mechanism [15,23]. While setting, it will create a network of microchannels and microporosity.…”

Bone Formation Analysis: Effect of Quantification Procedures on the Study Outcome

“…CaP powder was ball milled in a sequential milling pathway according to a previously developed process. 11 Low-molecular-weight (LMW, 17 kDa) acid-terminated PLGA (Purasorb; Purac Biomaterials BV) was used to produce microparticles. Microparticles with an average size of 20 mm were obtained using a ([water-inoil]-in-water) double-emulsion technique, as described previously.…”