Bioceramic implant induces cranial regrowth and restores bone defects in oral cavity

The reconstruction of major bone and soft-tissue injuries to the skull remains a difficult challenge owing to problems with available materials. The standard clinical practice is to transplant bone or to use plastic or metal implants. However, autologous bone has a limited availability and includes risks for the donor. Current plastic materials are associated with high complication and failure rates. In addition, the osseointegration of plastic and metal implants is inferior to that of bone.

“Growth factors and stem cells are thought to contribute to healing but haven’t yet been demonstrated to have any obvious advantages after administration in large, human skull defects,” said lead author Prof. Peter Thomsen, from the Department of Biomaterials at the University of Gothenburg, in a university press release.

Formation of natural bone

During experiments, the bioceramic implant was shown to transform into bone, with a morphology, ultrastructure and composition similar to that of natural skull bone. Experiments with titanium-only implants also resulted in bone formation, but only adjacent to the host bone.

The researchers used a new 3D-printed bioceramic material, which can be customised and attached to a titanium frame shaped like the missing part of the skull bone, in order to successfully heal large cranial defects by means of new bone formation without the addition of growth factors or stem cells.

“We can see the skull bone growing out, not just on remaining parts of the cranium but also centrally in the defect itself,” said Thomsen. “All the cells that we know are involved in bone formation and remodelling are recruited to, or are in place, in the central part of the defect and in soft tissue where the bioceramic was inserted. What happens is that the main constituent of the bioceramic, monetite, transforms into another material in the body: apatite,” he added.

Application for bone defects in the oral cavity

OssDsign, a portfolio company of Karolinska Development and patent holder of the novel bioceramic material, reported in a press release that the regenerative material can also be applied to restoration of bone defects in the oral cavity. In a clinical study conducted at Uppsala University Hospital, it was used in sinus augmentation to restore bone mass in the maxilla. According to the company, data from a six-month follow-up after implantation with the bioceramic material showed bone formation and a firm anchoring of the dental implants that had been placed during the operation.

Thomsen stressed the need for further research, both to investigate the molecular processes involved and in the form of additional clinical studies. “This principle will compete with existing treatment principles of bone transplantation, and plastic and metal implants,” he concluded.

The study, titled “In situ bone regeneration of large cranial defects using synthetic ceramic implants with a tailored composition and design”, was published on 27 October 2020 in Proceedings of the National Academy of Sciences of the United States of America.

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