PNIPU researchers have determined which jaw implants integrate best with the body.

Jaw and facial defects resulting from cysts, fractures, and cancer require prosthetic solutions. It's essential for the implant to integrate well without causing rejection, and it should also promote the formation of new tissue cells. To achieve this, jaw implants with a porous structure are utilized, which facilitate the rapid growth of bone tissue through the empty cells. This mesh can come in various shapes and sizes, making the selection of the most suitable model a critical consideration for both the surgeon and the patient. Researchers from Perm Polytechnic University, PGMU named after Academician E. A. Wagner, and DSTU conducted an experiment to determine which implant structure most effectively supports the rapid formation of new bone tissue.

2024-10-18 07:32:56https://naked-science.ru/article/column/chelyustnye-implanty-luch

The article has been published in the journal Mechanical Behavior of Biomedical Materials. The research was funded by a grant from the Russian Science Foundation.

Pore-structured titanium implants are actively used in surgery. The diameter of the cells in the lattice can vary, affecting the healing rate and strength of the prosthesis. To determine the most suitable sizes for its structure, scientists conducted an in vivo experiment on laboratory animals.

Using additive manufacturing technology, they created three types of implants with cell diameters of one, two, and three millimeters. The prostheses were then implanted into white rats and guinea pigs with artificially created defects in the lower jaw. The sample consisted of 82 laboratory animals, divided into three groups: monitored for two weeks, four months, and nine months. At the end of the experiment, researchers could study the newly formed tissues in the implant cells and the degree of bone adhesion to the prosthesis. Active tissue ingrowth was observed as early as two weeks post-implantation.

The surface of the prosthesis is covered with a thickened periosteum (the outer layer of bone), and a thin layer of connective tissue appears in the cells, which will later begin to form bone. The adhesion of the new tissue to the implant remains weak.
“After four months, the bone starts to fuse more actively with the implant, and homogeneous bone tissue forms within the cells. These processes occurred more rapidly in implants with a cell diameter of 3 mm: the struts and outer areas are filled with coarse fibrous, plastic, and connective tissue with large vessels,” explains Vladimir Vasiluk, Associate Professor of the Department of Maxillofacial Surgery at PGMU named after Academician E.A. Wagner, PhD in Medical Sciences.

After nine months, the implant shows a thickened periosteum. The one-millimeter cells are filled with fibrous tissue with isolated areas of lamellar bone, while the 2-3 millimeter cells are completely filled with it. There was also an observed increase in the volume of bone plates, the formation of blood vessels, and blood cells. The bone fused so tightly with the implant that in 68 percent of cases, separating them could only be done by sawing.

“The results of the study demonstrate that the processes of tissue formation within the implant begin as early as two weeks post-implantation, with the active phase occurring between 4 to 9 months. The formation of new tissue occurs faster in cells that have increased sizes of 2-3 millimeters – thus the healing rate of the prosthesis is reduced by three times (compared to a cell diameter of one millimeter),” says Polina Kilina, Associate Professor of the Department of "Innovative Technologies in Mechanical Engineering," leading researcher at the Biofluids Laboratory of PNIPU, PhD in Technical Sciences.

The joint research of scientists from Perm Polytechnic, PGMU named after Academician E.A. Wagner, and DSTU has allowed for the identification of which structures of jaw implants best facilitate the rapid formation of new bone tissue depending on the complexity of the jaw defect. For example, implants with three-millimeter cells are suitable for replacing cavities after the removal of periapical cysts, while implants sized 2-3 millimeters are appropriate for complete and partial defects. The results serve as a foundation for transitioning to clinical trials in humans.