Dental Implant Surface Enhancement and Osseointegration (2011)

Implant Dentistry  A Rapidly Evolving Practice 84 and crystallinity, roughness, chemical potential, strain hardening, the presence of impurities, thickness of titanium oxide layer, and the presence of metal and non-metal composites.Among these, wettability and free surface energy of an implant surface are considered to be very crucial.The implant surface, including topography, chemistry, surface charge, and wettability, has been described as an important factor to influence osseointegration.The influence of physical properties such as surface topography and roughness on osseointegration have translated to shorter healing times from implant placement to restoration (Cochran et al., 2002).The biologic basis underlying these clinical improvements continues to be explored (Kim et al., 2005, Lossdorfer et al., 2004).Albrektsson et al. (1981) suggested six factors that are particluarly important for the establishment of reliable osseointegration: implant material, implant design, surface conditions, status of the bone, surgical technique, and implant loading conditions. Biology of wound healing following implant placementWound healing involves a highly orchestrated sequence of events which is triggered by tissue injury involving soluble mediators, blood cells, extracellular matrix and parenchymal cells.Ultimately, it culminates in either partial or complete regeneration or repair.Fracture healing in bone occurs in four phases which include inflammation, soft and hard callus formation, and remodeling.Following a fracture, blood coagulation and hematoma formation takes place.This is followed by inflammation.Various chemical mediators such as thrombin and growth factors released by activated leukocytes and platelets in the hematoma serve as chemotactic signals to many cell types which play an important role in bone healing.Unlike soft tissue healing, bone healing does not lead to scarring.Instead it leads to restoration of the bony tissue.During successful implantation, insertion of metal implants into cortical bone eventually leads to complete healing.Following implant placement, unlike in fracture healing, implants extend into and persist in the marrow spaces and this may have a bearing on the healing process.Although implant healing must to some extent adjust to the presence of the implant, ultimately, sound bony tissues will be completely restored during wound healing.This adjustment involves imbedding the implant surface in a layer of bone, continuous with the original bone.Wound healing around a dental implant placed into a prepared osteotomy follows three stages of repair-Initial formation of a blood clot occurs through a biochemical activation followed by a cellular activation and finally a cellular response (Stanford and Schneider, 2004).During surgery, dental implant surfaces interact with blood components from ruptured blood vessels.Within a short period of time, various plasma proteins such as fibrin get adsorbed on the material surface.Fibrinogen is converted to fibrin and the complement and kinin systems become activated.As in fracture healing, the migration of bone cells in peri-implant healing will occur through the fibrin of a blood clot.Since fibrin has the potential to adhere to almost all surfaces, it can be anticipated that the migration of osteogenic cell populations towards the implant surface will occur.However, as the migration of cells through fibrin will cause retraction of the fibrin scaffold, the ability of an implant surface to retain this fibrin scaffold during the phase of wound contraction is critical in determining whether the migrating cells will reach the implant surface.Activation of platelets occurs as a result of interaction of platelets with the implant surface as well as the fibrin scaffold and this leads to thrombus formation and blood clotting.