Peri-implant Anatomy and Biology

When a dental implant comes in contact with bodily tissues and fluids, within milliseconds water, ions, and small biomolecules are absorbed. The osseointegration process can be compared to bone fracture healing. The process includes an inflammatory reaction, bone resorption, release of growth factors, and the attraction of osteoprogenitor chemotaxis cells. A differentiation of the cells into osteoblasts leads to bone formation at the dental implant surface. Extracellular matrix proteins modulate apatite crystal formation.29,43

As mentioned prior, the success of the dental implant begins with the initial immobility of the implant to the bone after surgical placement for bone to form at the implant-bone interface. New bone formation follows a specific sequence. Woven bone is quickly formed between the implant and bone with collagen fibrils. The bone will grow quickly and in all directions at a rate of approximately 100 um per day. After several months, woven bone is replaced by lamellar bone with layers of collagen fibrils and dense bone mineralization. Lamellar bone grows slowly, only a few microns per day. After approximately 18 months of healing, lamellar bone is resorbed and replaced.29

There are two important stability stages. The primary stability is the time of the surgical placement of the dental implant. Success of a dental implant is also determined by the placement of the implant, as well as the quality and quantity of the bone available for anchorage of the implant at the surgical site e.g., cortical bone. The secondary stability of the implant determines the percentage of contacts between the implant and bone. This is achieved over time with healing of the implant surface, as well as the quality and quantity of the adjacent bone.29 Both primary and secondary stability are crucial to the success of the dental implant (Figure 2). Posterior maxilla implants have been associated with lower success rates, compared to other sites, due to less bone density and support creating less bone-to-implant contact.21

Figure 2.
Photo showing a dental implant.
Courtesy of Dr. Samuel L. Corey