In implant dentistry, osseointegration refers to the direct functional and structural connection between the artificial tooth root and the existing bone. It is a critical and prerequisite process that determines the stability and long-term clinical success of the artificial tooth root and dental implant.
For the procedure to become successful, the implant body or tooth root must first interlock with the alveolar bone. The osseointegration process is quite complex, but it remarkably happens within only a few weeks after the surgery.
The first stage of implant surgery is to drill the surgical site to create a major defect. In the process, blood vessels are torn to enable a finely-tuned cell-to-cell communication and activate direct bone healing. What happens during this biodynamic process and complex sequence of wound healing and bone formation will determine the functional success of the dental implant.
Phase 1 – Hemostasis
The first phase of osseointegration occurs within seconds or minutes after the lesion was made by the dental surgeon. Blood then fuses in the surgical site and provides queues for subsequent healing. When the bleeding stops, naturally occurring collagen will heal the implant surface and close the ruptured blood vessel. The platelets will then facilitate a cross-linked fibre network and form a provisional matrix, which then adheres to the artificial tooth root, which is usually made of titanium or Zirconia. This matrix will then facilitate the bone healing process on the implant surface.
Phase 2 – Inflammatory Phase (Hours after surgery)
Hours after the surgery, the inflammatory phase will begin. The immune cells will clean the wound up to remove very fine bone chips, tissue debris and bacteria through reactive oxygen radicals. At this point, blood vessels will increasingly become porous. The immune cells will then start recruiting perivascular cells to assist in the development of blood vessels.
Phase 3 – Proliferative Phase
Days after the surgery, the perivascular cells will regulate angiogenesis, and differentiate into osteoblasts and fibroblasts. Osteoclasts will then allow the dissolution of existing bone substance through acidic pH values and proteolytic enzymes, while osteoblasts, which are stationary cells, will enable the forming of new bone through the expression of proteins such as collagen. They will also release carbonates and calcium phosphates.
Phase 4 – Remodelling Phase
Finally, the fourth phase or the reconstruction phase will occur weeks after the surgery. At this point, the implant should integrate to the bone and tissue. Osteocytes will communicate with nearby cells through dendritic projections to regulate the regeneration mechanism. Once phase four is complete, and the artificial tooth root has aggregated with the existing tissue and bone, the surgeon will place the implant tooth over the load-carrying implant.
Titanium and Zirconia are the materials of choice for implant bodies because of their superior mechanical properties and biocompatibility. It truly is a fascinating process. And given that implant technology is constantly evolving, the procedure will certainly reach perfection in the near future.