What should we expect once the implant is placed into our patient’s jaw? Studies have shown us that the implant’s osseointegration process is similar to our bone’s natural wound-healing process. Here’s a brief outline of the hard-tissue healing process.
Immediately After Placing the Implant
Immediately after placing the implant into the patient’s jaw, a microgap forms between the implant surface and host bone. This is usually 60 micrometres, but may extend to 100-500 micrometres over time (Wang, Zhang, & Miron, 2016). This gap contains a titanium oxide layer, blood plasma proteins and body fluids. These are then adsorbed onto the implant surface, forming a conditioning film. This film stimulates and induces cell attachment onto the implant surface (Wang et al., 2016).
The first cells to adhere onto the implant are mainly inflammatory cells (Wang et al., 2016), including neutrophils and later macrophages and monocytes. Thus, this is called the immune-inflammatory response (Wang et al., 2016). These cells remove debris, and secrete cytokines and growth factors. The latter two stimulate mesenchymal cells, angiogenesis and collagen matrix deposition.
Coagulum forming within the wound chamber (Salvi et al., 2015)
Meanwhile, a blood clot forms next to the implant surface. New blood vessels begin to form within the first 24 hours, and by the fourth day macrophages and monocytes infiltrate through these vessels to the bone wound (Wang et al., 2016). The blood clot gradually becomes replaced by mesenchymal cells from the bone marrow around the newly developing blood vessels. These cells differentiate into osteoblasts, attach to the implant and deposit a collagen matrix.
Osteogenesis
Bone formation begins by the 5th to 7th day (Wang et al., 2016). Two processes occur to integrate the implant into the bone. The first is contact osteogenesis, with bone apposition directly onto the implant itself. The second process is distance osteogenesis where new bone is formed at a distance from the implant but approaches it (Chai, Razali, Moharamzadeh, & Zafar, 2020). By the fourth week, these two processes have begun to join together. Within 8-12 weeks, the peri-implant interface is completely replaced by mature lamellae bone in direct contact with the implant surface (Wang et al., 2016). This completes the initial phase of osseointegration.
Old bone (OB) not yet in contact with the new pristine bone (Salvi et al., 2015)
Remodelling
Bone remodelling begins between the 6th and 12th week, but continues throughout life (Salvi et al., 2015). This involves resorption and formation of cortical bone near the implant surface. During the first year, it is normal to lose 1-1.5mm of crestal bone, and a further 0.2mm annually (Chai et al., 2020). Therefore, it is not necessarily considered pathological to find more than 3 or 4mm of bone loss after 10 or 15 years respectively.
Understanding the hard tissue healing process can help us better understand the integration of dental implants into our patient’s jaw. Specialist prosthodontists and periodontists at our Master Implant Programs in Melbourne and Adelaide provide you with the theory and hands-on training for implant surgery.
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References
Chai, W. L., Razali, M., Moharamzadeh, K., & Zafar, M. S. (2020). The hard and soft tissue interfaces with dental implants. In (pp. 173-201): Elsevier.
Salvi, G. E., Bosshardt, D. D., Lang, N. P., Abrahamsson, I., Berglundh, T., Lindhe, J., . . . Donos, N. (2015). Temporal sequence of hard and soft tissue healing around titanium dental implants. Periodontology 2000, 68(1), 135-152. doi:10.1111/prd.12054
Wang, Y., Zhang, Y., & Miron, R. J. (2016). Health, Maintenance, and Recovery of Soft Tissues around Implants. Clinical Implant Dentistry and Related Research, 18(3), 618-634. doi:10.1111/cid.12343
