In-Vivo Degradation Behavior and Osseointegration of 3D Powder-Printed Calcium Magnesium Phosphate Cement Scaffolds

Abstract

Calcium magnesium phosphate cements (CMPCs) are promising bone substitutes and experience great interest in research. Therefore, in-vivo degradation behavior, osseointegration and biocompatibility of three-dimensional (3D) powder-printed CMPC scaffolds were investigated in the present study. The materials Mg225 (Ca0.75Mg2.25(PO4)2) and Mg225d (Mg225 treated with diammonium hydrogen phosphate (DAHP)) were implanted as cylindrical scaffolds (h = 5 mm, Ø = 3.8 mm) in both lateral femoral condyles in rabbits and compared with tricalcium phosphate (TCP). Treatment with DAHP results in the precipitation of struvite, thus reducing pore size and overall porosity and increasing pressure stability. Over 6 weeks, the scaffolds were evaluated clinically, radiologically, with Micro-Computed Tomography (µCT) and histological examinations. All scaffolds showed excellent biocompatibility. X-ray and in-vivo µCT examinations showed a volume decrease and increasing osseointegration over time. Structure loss and volume decrease were most evident in Mg225. Histologically, all scaffolds degraded centripetally and were completely traversed by new bone, in which the remaining scaffold material was embedded. While after 6 weeks, Mg225d and TCP were still visible as a network, only individual particles of Mg225 were present. Based on these results, Mg225 and Mg225d appear to be promising bone substitutes for various loading situations that should be investigated further.

Additive Manufacturing Technologies for Fabrication of Biomaterials for Surgical Procedures in Dentistry: A Narrative Review

“…After phase 2, 89 articles were included in this review. Reading these articles, 5 categories of AM techniques described by the ISO/ASTM 52900 85 were identified: material jetting, 38 powder bed fusion, 32,87,91,100,101 vat photopolymerization, 15,20,64–66,70,77 binder jetting, 7,29,40,42,61,63,67,68,73,88,102,103 and material extrusion 8–14,16–19,21–28,30 31,33–37,39,41,43–60,62,69,71,72,74–76,78,79,89,90,92,104–109 (Fig 1). Only one of the selected studies used material jetting for the fabrication of scaffolds.…”

“…According to these studies, scaffolds should be easily adaptable to the bone defect, present surface wettability, and induce cell adsorption, proliferation, and differentiation. An interconnected pore architecture, controlled bioabsorption, and mechanical resistance are also expected 15,73,108 …”

Resorbable Mg2+-Containing Phosphates for Bone Tissue Repair

“…It is reported that cements with a 1.67 [Ca + Mg]/P ratio demonstrate high compressive strength up to 22 ± 3 MPa. Kowalewicz et al [129] studied the in vivo degradation, osseointegration, and biocompatibility of three-dimensional (3D) frameworks of CMPC. After 6 weeks of implantation, the Mg225 material based on Ca 0.75 Mg 2.25 (PO 4 ) 2 showed greater osteointegration and volume reduction compared to Mg225d based on Mg225 treated with ammonium hydrogen phosphate (DAHP).…”

Resorbable Mg²⁺-Containing Phosphates for Bone Tissue Repair

“…It is reported that cements with 1.67 [Ca+Mg]/P ratio demonstrate high compressive strength up to 22 ± 3 MPa. Kowalewicz et al [119] studied in vivo degradation, osseointegration and biocompatibility of three-dimensional (3D) frameworks of calcium magnesium phosphate cements (CMPC). After 6 weeks of implantation, the Mg225 material based on Ca0,75Mg2,25(PO4)2 showed greater osteointegration and volume reduction compared to Mg225d based on Mg225 treated with ammonium hydrogen phosphate (DAHP).…”