Effect of modified compound calcium phosphate cement on the differentiation and osteogenesis of bone mesenchymal stem cells

The osteogenesis effect of rhBMP2-loaded calcium phosphate cements in repairing dental extraction sockets

PURPOSE

After extracting impacted mandibular third molars (IMM3), the resulting bone loss at the distal surface of the distal root of mandibular second molars (MM2) is responsible for the poor stability of MM2. This study aimed to identify the clinical osteogenesis effect of recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded calcium phosphate cements (CPCs) and rhBMP-2 delivery systems (rhBMP-2/CPCs, named CPCII) on bone loss repair at the distal surface of the MM2 distal root after IMM3 extraction.

METHODS

Written informed consent was obtained from every participant whose IMM3 needed extraction. The impact of IMM3 on both sides was basically identical. From April 2014 to March 2016, extraction of IMM3 was performed in 9 patients (5 males/4 females, 26-42 years old). One side was randomly selected as the experimental group, and CPCII systems were implanted into the distal surface of the distal root in dental extraction sockets. The wounds on the other side were sutured and allowed to heal naturally (be treated as the control group). New bone formation in the alveolar fossa was detected 3 and 12 months after the operation by cone-beam computed tomography (CBCT) to measure the distance from the cementoenamel junction (CEJ) to the crest of the alveolar ridge (CAR).

RESULTS

The CAR-CEJ distance on the test side was less than that on the control side (P<0.5).

CONCLUSION

The quantity of new bone formation in the experimental group was greater than that in the control group. CPCII systems have osteogenic potential in the healing process of tooth extraction sockets.

Calcined Hydroxyapatite with Collagen I Foam Promotes Human MSC Osteogenic Differentiation

Collagen I-based foams were modified with calcined or noncalcined hydroxyapatite or calcium phosphates with various particle sizes and pores to monitor their effect on cell interactions. The resulting scaffolds thus differed in grain size, changing from nanoscale to microscopic, and possessed diverse morphological characteristics and resorbability. The materials' biological action was shown on human bone marrow MSCs. Scaffold morphology was identified by SEM. Using viability test, qPCR, and immunohistochemical staining, we evaluated the biological activity of all of the materials. This study revealed that the most suitable scaffold composition for osteogenesis induction is collagen I foam with calcined hydroxyapatite with a pore size of 360 ± 130 µm and mean particle size of 0.130 µm. The expression of osteogenic markers RunX2 and ColI mRNA was promoted, and a strong synthesis of extracellular protein osteocalcin was observed. ColI/calcined HAP scaffold showed significant osteogenic potential, and can be easily manipulated and tailored to the defect size, which gives it great potential for bone tissue engineering applications.