3D-Printed Biodegradable Meshes for Guided Bone Regeneration

3D-printed biodegradable meshes improve guided bone regeneration by combining custom fit, mechanical support, and enhanced tissue integration.

Oral and maxillofacial surgeons use GBR to augment bone before procedures such as dental implant placement. This bone graft procedure blocks soft-tissue invasion using a barrier membrane. Traditional GBR meshes are made of titanium or biodegradable materials, such as collagen. Titanium offers superior mechanical robustness but may cause stress shielding, leading to bone loss. Additionally, titanium meshes may require additional surgery for their removal. Collagen, on the other hand, does not provide sufficient strength for all surgical applications.

You can also read: Bioactive Bone Implants: The ELAINE Project’s 3D Printing Breakthrough.

In a novel prototype, researchers are proposing a new mesh material that may be more suitable for tissue regeneration. This 3D-printed, biodegradable composite comprises medical-grade poly(L-lactide-co-D, L-lactide (PLDLLA) and β-tricalcium phosphate (β-TCP). Using 3D printing and ARBURG Plastic Freeforming (APF) technology, this approach enables practitioners to create patient-specific meshes.

Fabricating Mesh Samples

Researchers created solid disks, porous disks (50% infill), and gyroid samples of the mesh. Gyroid surface patterns have been shown to enhance cell proliferation in previous studies. In this study, these gyroid samples had the same porosity as the porous disks. The disks’ pores averaged 243±17 μm, an ideal size for reducing fibrous tissue ingrowth. The gyroid designs exhibited larger pores (620±64 μm), which could facilitate angiogenesis and blood vessel growth.

Specimen Properties: Designing for Healing

To evaluate each specimen design, researchers evaluated their surface properties. The porous samples exhibited a surface roughness (Ra) of 2.27±0.38 μm, while the Ra of gyroid samples was 1.3±0.2 μm. In titanium meshes, a Ra of 1-2 μm is ideal for osteoblast integration. The solid samples had lower Ra values. This may be resultant of a slower cooling rate leading to improved droplet fusion thus lowering the contact angle. Contact angles below 80° increase hydrophilicity and improve cell adhesion on synthetic polymers.

During biaxial flexural testing, the solid samples exhibited significantly higher strength than the porous or gyroid samples. Though it is weaker than traditional titanium, the novel composite is sufficient for physiological conditions. It provides a balance between mechanical strength and bioresorbability. A model using solid beams and targeted porous regions could further optimize load-bearing capacity for tissue integration applications.

Mechanical and Biological Advantages in GBR

This study demonstrates an innovative design for GBR applications. The solid samples showed exceptional mechanical strength, while the porous and gyroid designs are beneficial for tissue integration. This approach eliminates the need for secondary surgical procedures often required by traditional titanium mesh.