Injectable and rapid‐setting calcium phosphate bone cement with dicalcium phosphate dihydrate

Abstract

Calcium phosphate cement (CPC) sets in situ with intimate adaptation to the contours of defect surfaces, and forms an implant having a structure and composition similar to hydroxyapatite, the putative mineral in teeth and bones. The objective of the present study was to develop an injectable CPC using dicalcium phosphate dihydrate (DCPD) with a high solubility for rapid setting. Two agents were incorporated to impart injectability and fast-hardening to the cement: a hardening accelerator (sodium phosphate) and a gelling agent (hydroxypropyl methylcellulose, HPMC). The cement with DCPD was designated as CPC(D), and the conventional cement was referred to as CPC(A). Using water without sodium phosphate, CPC(A) had a setting time of 82 +/- 6 min. In contrast, CPC(D) exhibited rapid setting with a time of 17 +/- 1 min. At 0.2 mol/L sodium phosphate, setting time for CPC(D) was 15 +/- 1 min, significantly faster than 40 +/- 2 min for CPC(A) (Tukey's at 0.95). Sodium phosphate decreased the paste injectability (measured as the paste mass extruded from the syringe divided by the original paste mass inside the syringe). However, the addition of HPMC dramatically increased the paste injectability. For CPC(D), the injectability was increased from 65% +/- 12% without HPMC to 98% +/- 1% with 1% HPMC. Injectability of CPC(A) was also doubled to 99% +/- 1%. The injectable and rapid-setting CPC(D) possessed flexural strength and elastic modulus values overlapping the reported values for sintered porous hydroxyapatite implants and cancellous bone. In summary, the rapid setting and relatively high strength and elastic modulus of CPC(D) should help the graft to quickly attain strength and geometrical integrity within a short period of time postoperatively. Furthermore, the injectability of CPC(D) may have potential for procedures involving defects with limited accessibility or narrow cavities, when there is a need for precise placement of the paste, and when using minimally invasive surgical techniques.

Strong, macroporous, and in situ-setting calcium phosphate cement-layered structures

“…Effects of porosity and chitosan reinforcement on (A) setting time and (B) flexural strength, for Group 1. Setting time for CPC using water without macropores was measured in a previous study [37]. In each plot, "*" indicates values that are not significantly different from each other (Tukey's multiple comparison test at 0.05).…”

Self-Setting Calcium Orthophosphate Formulations: Cements, Concretes, Pastes and Putties

“…The first self-setting calcium orthophosphate cement formulation consists of the equimolar mixture of TTCP and dicalcium phosphate (DCPA or DCPD) [96] which is mixed with water at a P/L ratio of 4:1; the paste hardened in about 30 min and formed CDHA [97,98]. This highly viscous, non-injectable paste can be molded and, therefore, is used mainly as a contouring material in craniofacial surgery.…”

Gas-Foaming Calcium Phosphate Cement Scaffold Encapsulating Human Umbilical Cord Stem Cells

“…[28][29][30]32 The mechanical properties and porosity of CPC were improved using degradable fibers, chitosan, and porogen. [34][35][36] In addition to scaffolds, cells are another important component of tissue engineering. Human umbilical cord mesenchymal stem cells (hUCMSC) were derived for tissue engineering.…”