In vivo evaluation of 3D printed polycaprolactone composite scaffold and recombinant human bone morphogenetic protein-2 for vertical bone augmentation with simultaneous implant placement on rabbit calvaria.

This study evaluated 3D printed polycaprolactone (PCL) composite scaffold and recombinant human bone morphogenetic protein-2 (rhBMP-2), loaded either onto a PCL composite scaffold or implant surface, for vertical bone augmentation with implant placement. Three-dimensional printed PCL frames were filled with powdered PCL, hydroxyapatite, and ß-tricalcium phosphate. RhBMP-2 was loaded to the PCL composite scaffolds and implant surfaces, and rhBMP-2 release was quantified for 21 days. Experimental implants were placed bilaterally on 20 rabbit calvaria, and the PCL composite scaffolds were vertically augmented. The randomly allocated experimental groups were divided by carrier and rhBMP-2 dosage as no rhBMP-2 (control), 5 µg rhBMP-2 loaded to PCL composite (Scaffold/rhBMP-2[5 µg]), 5 µg rhBMP-2 loaded to implant (Implant/rhBMP-2[5 µg]), 30 µg rhBMP-2 loaded to PCL composite (Scaffold/rhBMP-2[30 µg]), and 30 µg rhBMP-2 loaded to implant (Implant/rhBMP-2[30 µg]). Histologic and histometric analyses were conducted after 8 weeks. In both scaffold-loading and implant-loading, rhBMP-2 released initially rapidly, then slowly and constantly. Released rhBMP-2 totaled 23.02 ± 1.03% and 24.69 ± 1.14% in the scaffold-loaded and implant-loaded groups, respectively. There were no significant differences in histologic bone-implant contact (%). Peri-implant bone density (%) was significantly higher in the Scaffold/rhBMP-2(30 µg) and Implant/rhBMP-2(30 µg) groups. Total bone density (%) was not significantly different between the Scaffold/rhBMP-2(5 µg), Implant/rhBMP-2(5 µg), and control groups, or between the Scaffold/rhBMP-2(30 µg) and Implant/rhBMP-2(30 µg) groups, but was significantly higher in the Scaffold/rhBMP-2(30 µg) and Implant/rhBMP-2(30 µg) groups than in the controls. Three-dimensional printed PCL composite scaffold with rhBMP-2 produced vertical osteogenesis and osseointegration, regardless of rhBMP-2 loading to the PCL composite scaffold or implant surface.

Fabrication of Three-Dimensional Composite Scaffold for Simultaneous Alveolar Bone Regeneration in Dental Implant Installation.

Dental implant surgeries involve the insertion of implant fixtures into alveolar bones to replace missing teeth. When the availability of alveolar bone at the surgical site is insufficient, bone graft particles are filled in the insertion site for successful bone reconstruction. Bone graft particles induce bone regeneration over several months at the insertion site. Subsequently, implant fixtures can be inserted at the recipient site. Thus, conventional dental implant surgery is performed in several steps, which in turn increases the treatment period and cost involved. Therefore, to reduce surgical time and minimize treatment costs, a novel hybrid scaffold filled with bone graft particles that could be combined with implant fixtures is proposed. This scaffold is composed of a three-dimensionally (3D) printed polycaprolactone (PCL) frame and osteoconductive ceramic materials such as hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP). Herein, we analyzed the porosity, internal microstructure, and hydrophilicity of the hybrid scaffold. Additionally, Saos-2 cells were used to assess cell viability and proliferation. Two types of control scaffolds were used (a 3D printed PCL frame and a hybrid scaffold without HA/ß-TCP particles) for comparison, and the fabricated hybrid scaffold was verified to retain osteoconductive ceramic particles without losses. Moreover, the fabricated hybrid scaffold had high porosity and excellent microstructural interconnectivity. The in vitro Saos-2 cell experiments revealed superior cell proliferation and alkaline phosphatase assay results for the hybrid scaffold than the control scaffold. Hence, the proposed hybrid scaffold is a promising candidate for minimizing cost and duration of dental implant surgery.

Label-free quantitative proteomic analysis of human periodontal ligament stem cells by high-resolution mass spectrometry.

BACKGROUND AND OBJECTIVES: Proteome analysis of periodontal ligament stem cells (PDLSCs) could be used to study the function of PDL tissue. We used a label-free quantitative proteomic technique to investigate differentially expressed proteins (DEPs) in human PDLSCs (hPDLSCs) compared to human bone marrow mesenchymal stem cells (hBMSCs) and identify proteins specific to hPDLSCs. MATERIAL AND METHODS: hPDLSCs (n = 3) and hBMSCs (n = 3) were cultured and harvested for protein extraction and trypsin digestion. The proteomes of both cell types were analyzed by nano-liquid chromatography/tandem mass spectrometry. DEPs in hPDLSCs compared to hBMSCs were detected by label-free quantification and evaluated through signal transduction pathway and gene ontology (GO) analysis. RESULTS: In total, 690 and 771 proteins were identified from hPDLSCs and hBMSCs, of which 561 proteins were in common and 124 DEPs were found between hPDLSCs and hBMSCs. Fifty-eight proteins were expressed at significantly higher levels in hPDLSCs, whereas 66 proteins were expressed at lower levels compared to hBMSCs. The more highly expressed proteins were associated with translation and initiating protein synthesis, and lower expressed proteins were related to cell aging and metabolic processes. Proteins unique to hPDLSCs and hBMSCs were associated with translation and metabolic processes, respectively. CONCLUSION: Our results demonstrate evidence of distinct differences in protein expression between hPDLSCs and hBMSCs by using label-free quantitative proteomic analysis which was the first attempt in this field. DEPs included previously reported hPDLSC marker proteins and novel marker candidates, such as microtubule-associated protein, CTP synthase 1 and stathmin, which could be the markers for developing periodontal disease diagnostics and therapies.