Biomedical Engineering Reference
In-Depth Information
FIGURE 5.4
Scheme showing blood composition and components that primarily
interact with surface of dental implants.
adhesion by cell-binding RGD domain (arg-gly-asp). This RGD sequence interacts with integrin pres-
ent on the cell membrane
[26]
. Interactions between cell membrane integrins and proteins coated onto
implant surface play a key role in adhesion of many cells types. After proteins absorption, the osseo-
integration is characterized by platelets adhesion and fibrin clots formation at the injured blood vessels
site. It has been shown that implants in contact with platelet-rich plasma (PRP) with a platelet concen-
tration of approximately 1,000,000 protein/μl have a positive effect on osseointegration. At lower con-
centrations of PRP, the effect was not optimal, while higher concentrations resulted in a paradoxically
inhibitory effect of bone regeneration. Other studies were not in agreement with this PRP beneficial
effect on the osseointegration of dental implants
[27]
. The assessment of bioactivity of surface treated
dental implants should be tested
in vitro
using biological fluids containing blood components
[2]
.
5.4
INTERACTIONS BETWEEN SURFACES AND MSCs
Following blood clotting around dental implants, several cells interact with surfaces for tissue heal-
ing. MSCs attracted to the injured site by chemotactic factors have a determinant role in peri-implant
tissue healing.
5.4.1
Origin of MSCs
MSCs are stem cells derived from somatic tissue which can be differentiated into mesenchymal line-
ages such as bone, cartilage, fat, and skin. In addition, MSCs are present in many connective tissues
and blood at low concentrations serving as a sort of internal repair system. MSCs are distinguished
