Speaker
Description
"INTRODUCTION
One of the main functions of guided bone regeneration (GBR) barriers are to preserve the bone graft and maintain its mechanical stability during the healing process. Personalized metallic meshes meet GBR demands as well as a good predictable tissue regeneration1. Although they offer good performance in terms of tissue regeneration, these metallic meshes present several drawbacks such as a second surgery to extract the mesh, autologous bone extraction from other anatomical locations, or mesh exposition. These problems cause extra pain and morbidity to the patient. Therefore, this project aims to substitute the use of metallic meshes with patient-specific biodegradable implants based on polycaprolactone (PCL), enriched with bioactive microparticles (MPs) to stimulate angiogenic and osteogenic processes.
METHODOLOGY
Different PCL scaffolds (PCLA, PCLB, PCLC) with bioactive MPs developed in our group were 3D printed (3D Discovery, RegenHU) with high interconnected porosity. The degradation behavior of scaffolds was evaluated in vitro under physiological conditions (HEPES 10mM, pH 7.4, 37ºC) for one year. The viability of human gingival fibroblasts (hGFib) and human mesenchymal stem cells (hMSC) seeded on scaffolds was assessed by Alamar Blue, and imaging. Cytotoxicity (LDH assay) and the expression of different proteins (ELISA) related with angiogenesis and osteogenesis were also evaluated. The in vivo performance of these scaffolds was studied using an in vivo subcutaneous mice model. In order to assess a correct fit of the personalized implants, 3D printed prototypes were tested with polyamide models kindly provided by AVINENT® Implant System.
RESULTS
SEM and MicroCT images showed homogeneous MPs dispersion and macroporosity of 3D printed scaffolds. Minimum scaffolds weight loss was observed after one year. Confocal images indicated complete colonization of scaffolds by hGFib. Similarly, good biocompatibility was observed in hMSC cultures. Analysis of protein expression by ELISA showed an increase in the levels of vascular endothelial growth factor (VEGF) which is related to neovascularization promotion. In the in vivo studies, an absence of acute inflammation and complete tissue integration were observed, indicating scaffold biocompatibility. Furthermore, blood vessels infiltration through scaffolds porosity was identified after one-month implantation. Moreover, personalized prototypes were successfully 3D printed from clinical cases and studied with polyamide bone defects models, obtaining a proper fit of the implant to the defect site.
CONCLUSION
This work shows a promising alternative to the use of metallic meshes, with bioactive and biodegradable materials to offer a personalized solution for GBR, avoiding their main drawbacks. Additional in vitro assays and an in vivo calvaria study are ongoing to support the results achieved.
REFERENCES
- Xie, Y., S., Zhang, et al., Int. J. Oral Sci., 12, 37, (2020).
ACKNOWLEDGMENTS
This project is being developed in collaboration and with funding from AVINENT® Implant System. Authors would like to thank AGAUR for founding with “Doctorat Industrial” grant (2017DI076) and Dr. Elena Xuriguera from the University of Barcelona for her help in performing mechanical testing."
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